From 0ecea78e0c97c19b7ab987868e0a95808f5aaafc Mon Sep 17 00:00:00 2001
From: Jan Kassens <jkassens@meta.com>
Date: Thu, 2 Nov 2023 13:43:14 -0400
Subject: [PATCH 1/3] rename unstable_Offscreen to unstable_Activity

---
 ...DOMServerPartialHydration-test.internal.js |  22 +-
 .../src/__tests__/ReactCache-test.js          |  10 +-
 .../src/__tests__/ReactDeferredValue-test.js  |  24 +-
 .../src/__tests__/ReactOffscreen-test.js      | 290 +++++++++---------
 .../ReactOffscreenStrictMode-test.js          |  32 +-
 .../__tests__/ReactOffscreenSuspense-test.js  |  32 +-
 .../ReactSuspenseyCommitPhase-test.js         |   8 +-
 .../__tests__/ReactTransitionTracing-test.js  |   8 +-
 packages/react/index.classic.fb.js            |   2 +-
 packages/react/index.experimental.js          |   2 +-
 packages/react/index.js                       |   2 +-
 packages/react/index.modern.fb.js             |   2 +-
 packages/react/src/React.js                   |   2 +-
 13 files changed, 216 insertions(+), 220 deletions(-)

diff --git a/packages/react-dom/src/__tests__/ReactDOMServerPartialHydration-test.internal.js b/packages/react-dom/src/__tests__/ReactDOMServerPartialHydration-test.internal.js
index 2468e6303a29..9d9f35eb01c2 100644
--- a/packages/react-dom/src/__tests__/ReactDOMServerPartialHydration-test.internal.js
+++ b/packages/react-dom/src/__tests__/ReactDOMServerPartialHydration-test.internal.js
@@ -10,15 +10,15 @@
 
 'use strict';
 
+let Activity;
 let React = require('react');
 let ReactDOM;
 let ReactDOMClient;
 let ReactDOMServer;
-let Scheduler;
 let ReactFeatureFlags;
+let Scheduler;
 let Suspense;
 let SuspenseList;
-let Offscreen;
 let useSyncExternalStore;
 let act;
 let IdleEventPriority;
@@ -112,8 +112,8 @@ describe('ReactDOMServerPartialHydration', () => {
     act = require('internal-test-utils').act;
     ReactDOMServer = require('react-dom/server');
     Scheduler = require('scheduler');
+    Activity = React.unstable_Activity;
     Suspense = React.Suspense;
-    Offscreen = React.unstable_Offscreen;
     useSyncExternalStore = React.useSyncExternalStore;
     if (gate(flags => flags.enableSuspenseList)) {
       SuspenseList = React.unstable_SuspenseList;
@@ -778,7 +778,7 @@ describe('ReactDOMServerPartialHydration', () => {
     expect(span).not.toBe(span2);
 
     if (gate(flags => flags.dfsEffectsRefactor)) {
-      // The effects list refactor causes this to be null because the Suspense Offscreen's child
+      // The effects list refactor causes this to be null because the Suspense Activity's child
       // is null. However, since we can't hydrate Suspense in legacy this change in behavior is ok
       expect(ref.current).toBe(null);
     } else {
@@ -3152,14 +3152,14 @@ describe('ReactDOMServerPartialHydration', () => {
   });
 
   // @gate enableOffscreen
-  it('a visible Offscreen component acts like a fragment', async () => {
+  it('a visible Activity component acts like a fragment', async () => {
     const ref = React.createRef();
 
     function App() {
       return (
-        <Offscreen mode="visible">
+        <Activity mode="visible">
           <span ref={ref}>Child</span>
-        </Offscreen>
+        </Activity>
       );
     }
 
@@ -3169,7 +3169,7 @@ describe('ReactDOMServerPartialHydration', () => {
     const container = document.createElement('div');
     container.innerHTML = finalHTML;
 
-    // Visible Offscreen boundaries behave exactly like fragments: a
+    // Visible Activity boundaries behave exactly like fragments: a
     // pure indirection.
     expect(container).toMatchInlineSnapshot(`
       <div>
@@ -3188,7 +3188,7 @@ describe('ReactDOMServerPartialHydration', () => {
   });
 
   // @gate enableOffscreen
-  it('a hidden Offscreen component is skipped over during server rendering', async () => {
+  it('a hidden Activity component is skipped over during server rendering', async () => {
     const visibleRef = React.createRef();
 
     function HiddenChild() {
@@ -3201,9 +3201,9 @@ describe('ReactDOMServerPartialHydration', () => {
       return (
         <>
           <span ref={visibleRef}>Visible</span>
-          <Offscreen mode="hidden">
+          <Activity mode="hidden">
             <HiddenChild />
-          </Offscreen>
+          </Activity>
         </>
       );
     }
diff --git a/packages/react-reconciler/src/__tests__/ReactCache-test.js b/packages/react-reconciler/src/__tests__/ReactCache-test.js
index 7709652467e8..83d7f0b69760 100644
--- a/packages/react-reconciler/src/__tests__/ReactCache-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactCache-test.js
@@ -6,7 +6,7 @@ let Scheduler;
 let assertLog;
 let act;
 let Suspense;
-let Offscreen;
+let Activity;
 let useCacheRefresh;
 let startTransition;
 let useState;
@@ -27,7 +27,7 @@ describe('ReactCache', () => {
     act = require('internal-test-utils').act;
     Suspense = React.Suspense;
     cache = React.cache;
-    Offscreen = React.unstable_Offscreen;
+    Activity = React.unstable_Activity;
     getCacheSignal = React.unstable_getCacheSignal;
     useCacheRefresh = React.unstable_useCacheRefresh;
     startTransition = React.startTransition;
@@ -1578,10 +1578,10 @@ describe('ReactCache', () => {
 
   // @gate enableOffscreen
   // @gate enableCache
-  test('prerender a new cache boundary inside an Offscreen tree', async () => {
+  test('prerender a new cache boundary inside an Activity tree', async () => {
     function App({prerenderMore}) {
       return (
-        <Offscreen mode="hidden">
+        <Activity mode="hidden">
           <div>
             {prerenderMore ? (
               <Cache>
@@ -1589,7 +1589,7 @@ describe('ReactCache', () => {
               </Cache>
             ) : null}
           </div>
-        </Offscreen>
+        </Activity>
       );
     }
 
diff --git a/packages/react-reconciler/src/__tests__/ReactDeferredValue-test.js b/packages/react-reconciler/src/__tests__/ReactDeferredValue-test.js
index 0c7fe7af103f..b34bc80a18f7 100644
--- a/packages/react-reconciler/src/__tests__/ReactDeferredValue-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactDeferredValue-test.js
@@ -16,7 +16,7 @@ let useDeferredValue;
 let useMemo;
 let useState;
 let Suspense;
-let Offscreen;
+let Activity;
 let assertLog;
 let waitForPaint;
 let textCache;
@@ -34,7 +34,7 @@ describe('ReactDeferredValue', () => {
     useMemo = React.useMemo;
     useState = React.useState;
     Suspense = React.Suspense;
-    Offscreen = React.unstable_Offscreen;
+    Activity = React.unstable_Activity;
 
     const InternalTestUtils = require('internal-test-utils');
     assertLog = InternalTestUtils.assertLog;
@@ -585,9 +585,7 @@ describe('ReactDeferredValue', () => {
       const [shouldShow, setState] = useState(false);
       revealContent = () => setState(true);
       return (
-        <Offscreen mode={shouldShow ? 'visible' : 'hidden'}>
-          {children}
-        </Offscreen>
+        <Activity mode={shouldShow ? 'visible' : 'hidden'}>{children}</Activity>
       );
     }
 
@@ -634,9 +632,7 @@ describe('ReactDeferredValue', () => {
       const [shouldShow, setState] = useState(false);
       revealContent = () => setState(true);
       return (
-        <Offscreen mode={shouldShow ? 'visible' : 'hidden'}>
-          {children}
-        </Offscreen>
+        <Activity mode={shouldShow ? 'visible' : 'hidden'}>{children}</Activity>
       );
     }
 
@@ -695,9 +691,9 @@ describe('ReactDeferredValue', () => {
 
       function Container({text, shouldShow}) {
         return (
-          <Offscreen mode={shouldShow ? 'visible' : 'hidden'}>
+          <Activity mode={shouldShow ? 'visible' : 'hidden'}>
             <App text={text} />
-          </Offscreen>
+          </Activity>
         );
       }
 
@@ -736,9 +732,9 @@ describe('ReactDeferredValue', () => {
 
       function Container({text, shouldShow}) {
         return (
-          <Offscreen mode={shouldShow ? 'visible' : 'hidden'}>
+          <Activity mode={shouldShow ? 'visible' : 'hidden'}>
             <App text={text} />
-          </Offscreen>
+          </Activity>
         );
       }
 
@@ -781,9 +777,9 @@ describe('ReactDeferredValue', () => {
 
       function Container({text, shouldShow}) {
         return (
-          <Offscreen mode={shouldShow ? 'visible' : 'hidden'}>
+          <Activity mode={shouldShow ? 'visible' : 'hidden'}>
             <App text={text} />
-          </Offscreen>
+          </Activity>
         );
       }
 
diff --git a/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js b/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js
index 120424ce1bf4..dabc562c97c9 100644
--- a/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js
@@ -3,7 +3,7 @@ let ReactNoop;
 let Scheduler;
 let act;
 let LegacyHidden;
-let Offscreen;
+let Activity;
 let useState;
 let useLayoutEffect;
 let useEffect;
@@ -23,7 +23,7 @@ describe('ReactOffscreen', () => {
     Scheduler = require('scheduler');
     act = require('internal-test-utils').act;
     LegacyHidden = React.unstable_LegacyHidden;
-    Offscreen = React.unstable_Offscreen;
+    Activity = React.unstable_Activity;
     useState = React.useState;
     useLayoutEffect = React.useLayoutEffect;
     useEffect = React.useEffect;
@@ -226,9 +226,9 @@ describe('ReactOffscreen', () => {
     // Mount hidden tree.
     await act(() => {
       root.render(
-        <Offscreen mode="hidden">
+        <Activity mode="hidden">
           <Child />
-        </Offscreen>,
+        </Activity>,
       );
     });
     // No layout effect.
@@ -238,9 +238,9 @@ describe('ReactOffscreen', () => {
     // Unhide the tree. The layout effect is mounted.
     await act(() => {
       root.render(
-        <Offscreen mode="visible">
+        <Activity mode="visible">
           <Child />
-        </Offscreen>,
+        </Activity>,
       );
     });
     assertLog(['Child', 'Mount layout']);
@@ -262,9 +262,9 @@ describe('ReactOffscreen', () => {
     const root = ReactNoop.createRoot();
     await act(() => {
       root.render(
-        <Offscreen mode="visible">
+        <Activity mode="visible">
           <Child />
-        </Offscreen>,
+        </Activity>,
       );
     });
     assertLog(['Child', 'Mount layout']);
@@ -273,9 +273,9 @@ describe('ReactOffscreen', () => {
     // Hide the tree. The layout effect is unmounted.
     await act(() => {
       root.render(
-        <Offscreen mode="hidden">
+        <Activity mode="hidden">
           <Child />
-        </Offscreen>,
+        </Activity>,
       );
     });
     assertLog(['Unmount layout', 'Child']);
@@ -284,9 +284,9 @@ describe('ReactOffscreen', () => {
     // Unhide the tree. The layout effect is re-mounted.
     await act(() => {
       root.render(
-        <Offscreen mode="visible">
+        <Activity mode="visible">
           <Child />
-        </Offscreen>,
+        </Activity>,
       );
     });
     assertLog(['Child', 'Mount layout']);
@@ -295,7 +295,7 @@ describe('ReactOffscreen', () => {
 
   // @gate enableOffscreen
   it('nested offscreen does not call componentWillUnmount when hidden', async () => {
-    // This is a bug that appeared during production test of <unstable_Offscreen />.
+    // This is a bug that appeared during production test of <unstable_Activity />.
     // It is a very specific scenario with nested Offscreens. The inner offscreen
     // goes from visible to hidden in synchronous update.
     class ClassComponent extends React.Component {
@@ -316,11 +316,11 @@ describe('ReactOffscreen', () => {
     await act(() => {
       // Outer and inner offscreen are hidden.
       root.render(
-        <Offscreen mode={'hidden'}>
-          <Offscreen mode={'hidden'}>
+        <Activity mode={'hidden'}>
+          <Activity mode={'hidden'}>
             <ClassComponent />
-          </Offscreen>
-        </Offscreen>,
+          </Activity>
+        </Activity>,
       );
     });
 
@@ -330,11 +330,11 @@ describe('ReactOffscreen', () => {
     await act(() => {
       // Inner offscreen is visible.
       root.render(
-        <Offscreen mode={'hidden'}>
-          <Offscreen mode={'visible'}>
+        <Activity mode={'hidden'}>
+          <Activity mode={'visible'}>
             <ClassComponent />
-          </Offscreen>
-        </Offscreen>,
+          </Activity>
+        </Activity>,
       );
     });
 
@@ -344,11 +344,11 @@ describe('ReactOffscreen', () => {
     await act(() => {
       // Inner offscreen is hidden.
       root.render(
-        <Offscreen mode={'hidden'}>
-          <Offscreen mode={'hidden'}>
+        <Activity mode={'hidden'}>
+          <Activity mode={'hidden'}>
             <ClassComponent />
-          </Offscreen>
-        </Offscreen>,
+          </Activity>
+        </Activity>,
       );
     });
 
@@ -358,11 +358,11 @@ describe('ReactOffscreen', () => {
     await act(() => {
       // Inner offscreen is visible.
       root.render(
-        <Offscreen mode={'hidden'}>
-          <Offscreen mode={'visible'}>
+        <Activity mode={'hidden'}>
+          <Activity mode={'visible'}>
             <ClassComponent />
-          </Offscreen>
-        </Offscreen>,
+          </Activity>
+        </Activity>,
       );
     });
 
@@ -372,11 +372,11 @@ describe('ReactOffscreen', () => {
       // Outer offscreen is visible.
       // Inner offscreen is hidden.
       root.render(
-        <Offscreen mode={'visible'}>
-          <Offscreen mode={'hidden'}>
+        <Activity mode={'visible'}>
+          <Activity mode={'hidden'}>
             <ClassComponent />
-          </Offscreen>
-        </Offscreen>,
+          </Activity>
+        </Activity>,
       );
     });
 
@@ -386,11 +386,11 @@ describe('ReactOffscreen', () => {
       // Outer offscreen is hidden.
       // Inner offscreen is visible.
       root.render(
-        <Offscreen mode={'hidden'}>
-          <Offscreen mode={'visible'}>
+        <Activity mode={'hidden'}>
+          <Activity mode={'visible'}>
             <ClassComponent />
-          </Offscreen>
-        </Offscreen>,
+          </Activity>
+        </Activity>,
       );
     });
 
@@ -413,9 +413,9 @@ describe('ReactOffscreen', () => {
     await act(() => {
       // Start the tree hidden. The layout effect is not mounted.
       root.render(
-        <Offscreen mode="hidden">
+        <Activity mode="hidden">
           <Child />
-        </Offscreen>,
+        </Activity>,
       );
     });
     assertLog(['Child']);
@@ -424,9 +424,9 @@ describe('ReactOffscreen', () => {
     // Show the tree. The layout effect is mounted.
     await act(() => {
       root.render(
-        <Offscreen mode="visible">
+        <Activity mode="visible">
           <Child />
-        </Offscreen>,
+        </Activity>,
       );
     });
     assertLog(['Child', 'Mount layout']);
@@ -435,9 +435,9 @@ describe('ReactOffscreen', () => {
     // Hide the tree again. The layout effect is un-mounted.
     await act(() => {
       root.render(
-        <Offscreen mode="hidden">
+        <Activity mode="hidden">
           <Child />
-        </Offscreen>,
+        </Activity>,
       );
     });
     assertLog(['Unmount layout', 'Child']);
@@ -461,9 +461,9 @@ describe('ReactOffscreen', () => {
 
     await act(() => {
       root.render(
-        <Offscreen mode="visible">
+        <Activity mode="visible">
           <Child />
-        </Offscreen>,
+        </Activity>,
       );
     });
     assertLog(['Child', 'Mount layout']);
@@ -472,9 +472,9 @@ describe('ReactOffscreen', () => {
     // Hide the tree. The layout effect is unmounted.
     await act(() => {
       root.render(
-        <Offscreen mode="hidden">
+        <Activity mode="hidden">
           <Child />
-        </Offscreen>,
+        </Activity>,
       );
     });
     assertLog(['Unmount layout', 'Child']);
@@ -536,9 +536,9 @@ describe('ReactOffscreen', () => {
     const root = ReactNoop.createRoot();
     await act(() => {
       root.render(
-        <Offscreen mode="hidden">
+        <Activity mode="hidden">
           <span>Hi</span>
-        </Offscreen>,
+        </Activity>,
       );
     });
     expect(root).toMatchRenderedOutput(<span hidden={true}>Hi</span>);
@@ -546,10 +546,10 @@ describe('ReactOffscreen', () => {
     // Insert a new node into the hidden tree
     await act(() => {
       root.render(
-        <Offscreen mode="hidden">
+        <Activity mode="hidden">
           <span>Hi</span>
           <span>Something new</span>
-        </Offscreen>,
+        </Activity>,
       );
     });
     expect(root).toMatchRenderedOutput(
@@ -566,9 +566,9 @@ describe('ReactOffscreen', () => {
     const root = ReactNoop.createRoot();
     await act(() => {
       root.render(
-        <Offscreen mode="hidden">
+        <Activity mode="hidden">
           <span>Hi</span>
-        </Offscreen>,
+        </Activity>,
       );
     });
     expect(root).toMatchRenderedOutput(<span hidden={true}>Hi</span>);
@@ -576,20 +576,20 @@ describe('ReactOffscreen', () => {
     // Set the `hidden` prop to on an already hidden node
     await act(() => {
       root.render(
-        <Offscreen mode="hidden">
+        <Activity mode="hidden">
           <span hidden={false}>Hi</span>
-        </Offscreen>,
+        </Activity>,
       );
     });
-    // It should still be hidden, because the Offscreen container overrides it
+    // It should still be hidden, because the Activity container overrides it
     expect(root).toMatchRenderedOutput(<span hidden={true}>Hi</span>);
 
     // Unhide the boundary
     await act(() => {
       root.render(
-        <Offscreen mode="visible">
+        <Activity mode="visible">
           <span hidden={true}>Hi</span>
-        </Offscreen>,
+        </Activity>,
       );
     });
     // It should still be hidden, because of the prop
@@ -598,9 +598,9 @@ describe('ReactOffscreen', () => {
     // Remove the `hidden` prop
     await act(() => {
       root.render(
-        <Offscreen mode="visible">
+        <Activity mode="visible">
           <span>Hi</span>
-        </Offscreen>,
+        </Activity>,
       );
     });
     // Now it's visible
@@ -661,9 +661,9 @@ describe('ReactOffscreen', () => {
       return (
         <>
           <Text text={'Outer: ' + outer} />
-          <Offscreen mode={show ? 'visible' : 'hidden'}>
+          <Activity mode={show ? 'visible' : 'hidden'}>
             <Child />
-          </Offscreen>
+          </Activity>
         </>
       );
     }
@@ -742,7 +742,7 @@ describe('ReactOffscreen', () => {
   });
 
   // @gate enableOffscreen
-  it('regression: Offscreen instance is sometimes null during setState', async () => {
+  it('regression: Activity instance is sometimes null during setState', async () => {
     let setState;
     function Child() {
       const [state, _setState] = useState('Initial');
@@ -752,7 +752,7 @@ describe('ReactOffscreen', () => {
 
     const root = ReactNoop.createRoot();
     await act(() => {
-      root.render(<Offscreen hidden={false} />);
+      root.render(<Activity hidden={false} />);
     });
     assertLog([]);
     expect(root).toMatchRenderedOutput(null);
@@ -761,10 +761,10 @@ describe('ReactOffscreen', () => {
       // Partially render a component
       startTransition(() => {
         root.render(
-          <Offscreen hidden={false}>
+          <Activity hidden={false}>
             <Child />
             <Text text="Sibling" />
-          </Offscreen>,
+          </Activity>,
         );
       });
       await waitFor(['Initial']);
@@ -776,7 +776,7 @@ describe('ReactOffscreen', () => {
 
       // Something attempts to update the never-mounted component. When this
       // regression test was written, we would walk up the component's return
-      // path and reach an unmounted Offscreen component fiber. Its `stateNode`
+      // path and reach an unmounted Activity component fiber. Its `stateNode`
       // would be null because it was nulled out when it was deleted, but there
       // was no null check before we accessed it. A weird edge case but we must
       // account for it.
@@ -805,9 +805,9 @@ describe('ReactOffscreen', () => {
     // Initial render
     await act(() => {
       root.render(
-        <Offscreen mode="hidden">
+        <Activity mode="hidden">
           <Child />
-        </Offscreen>,
+        </Activity>,
       );
     });
     assertLog(['A']);
@@ -829,9 +829,9 @@ describe('ReactOffscreen', () => {
     // revealed, both the B callback and C callback should fire, in that order.
     await act(() => {
       root.render(
-        <Offscreen mode="visible">
+        <Activity mode="visible">
           <Child />
-        </Offscreen>,
+        </Activity>,
       );
       child.setState({text: 'C'}, () => {
         Scheduler.log('C update finished');
@@ -862,9 +862,9 @@ describe('ReactOffscreen', () => {
     const root = ReactNoop.createRoot();
     await act(() => {
       root.render(
-        <Offscreen mode="visible">
+        <Activity mode="visible">
           <Child />
-        </Offscreen>,
+        </Activity>,
       );
     });
     assertLog(['componentDidMount']);
@@ -872,9 +872,9 @@ describe('ReactOffscreen', () => {
     // Hide the class component
     await act(() => {
       root.render(
-        <Offscreen mode="hidden">
+        <Activity mode="hidden">
           <Child />
-        </Offscreen>,
+        </Activity>,
       );
     });
     assertLog(['componentWillUnmount']);
@@ -883,9 +883,9 @@ describe('ReactOffscreen', () => {
     // componentDidUpdate.
     await act(() => {
       root.render(
-        <Offscreen mode="visible">
+        <Activity mode="visible">
           <Child />
-        </Offscreen>,
+        </Activity>,
       );
     });
     assertLog(['componentDidMount']);
@@ -910,9 +910,9 @@ describe('ReactOffscreen', () => {
       const root = ReactNoop.createRoot();
       await act(() => {
         root.render(
-          <Offscreen mode="visible">
+          <Activity mode="visible">
             <Child key="B" label="B" />
-          </Offscreen>,
+          </Activity>,
         );
       });
       assertLog(['Mount B']);
@@ -920,9 +920,9 @@ describe('ReactOffscreen', () => {
       // Hide the component
       await act(() => {
         root.render(
-          <Offscreen mode="hidden">
+          <Activity mode="hidden">
             <Child key="B" label="B" />
-          </Offscreen>,
+          </Activity>,
         );
       });
       assertLog(['Unmount B']);
@@ -930,11 +930,11 @@ describe('ReactOffscreen', () => {
       // Reappear the component and also add some new siblings.
       await act(() => {
         root.render(
-          <Offscreen mode="visible">
+          <Activity mode="visible">
             <Child key="A" label="A" />
             <Child key="B" label="B" />
             <Child key="C" label="C" />
-          </Offscreen>,
+          </Activity>,
         );
       });
       // B's effect should fire in between A and C even though it's been reused
@@ -966,9 +966,9 @@ describe('ReactOffscreen', () => {
       const root = ReactNoop.createRoot();
       await act(() => {
         root.render(
-          <Offscreen mode="visible">
+          <Activity mode="visible">
             <Child key="B" ref={bRef} label="B" />
-          </Offscreen>,
+          </Activity>,
         );
       });
       assertLog(['Mount B']);
@@ -980,9 +980,9 @@ describe('ReactOffscreen', () => {
       // Hide the component
       await act(() => {
         root.render(
-          <Offscreen mode="hidden">
+          <Activity mode="hidden">
             <Child key="B" ref={bRef} label="B" />
-          </Offscreen>,
+          </Activity>,
         );
       });
       assertLog(['Unmount B']);
@@ -993,11 +993,11 @@ describe('ReactOffscreen', () => {
           Scheduler.log('setState callback B');
         });
         root.render(
-          <Offscreen mode="visible">
+          <Activity mode="visible">
             <Child key="A" label="A" />
             <Child key="B" ref={bRef} label="B" />
             <Child key="C" label="C" />
-          </Offscreen>,
+          </Activity>,
         );
       });
       // B's effect should fire in between A and C even though it's been reused
@@ -1008,7 +1008,7 @@ describe('ReactOffscreen', () => {
   );
 
   // @gate enableOffscreen
-  it('defer passive effects when prerendering a new Offscreen tree', async () => {
+  it('defer passive effects when prerendering a new Activity tree', async () => {
     function Child({label}) {
       useEffect(() => {
         Scheduler.log('Mount ' + label);
@@ -1023,9 +1023,9 @@ describe('ReactOffscreen', () => {
       return (
         <>
           <Child label="Shell" />
-          <Offscreen mode={showMore ? 'visible' : 'hidden'}>
+          <Activity mode={showMore ? 'visible' : 'hidden'}>
             <Child label="More" />
-          </Offscreen>
+          </Activity>
         </>
       );
     }
@@ -1104,7 +1104,7 @@ describe('ReactOffscreen', () => {
       'Shell',
       'Mount Shell',
 
-      // Then prerender the hidden extra context. Unlike Offscreen, the passive
+      // Then prerender the hidden extra context. Unlike Activity, the passive
       // effects in the hidden tree *should* fire
       'More',
       'Mount More',
@@ -1139,14 +1139,14 @@ describe('ReactOffscreen', () => {
 
     function App({show, step}) {
       return (
-        <Offscreen mode={show ? 'visible' : 'hidden'}>
+        <Activity mode={show ? 'visible' : 'hidden'}>
           {useMemo(
             () => (
               <Child step={step} />
             ),
             [step],
           )}
-        </Offscreen>
+        </Activity>
       );
     }
 
@@ -1205,9 +1205,9 @@ describe('ReactOffscreen', () => {
 
     function App({show}) {
       return (
-        <Offscreen mode={show ? 'visible' : 'hidden'}>
+        <Activity mode={show ? 'visible' : 'hidden'}>
           <Parent />
-        </Offscreen>
+        </Activity>
       );
     }
 
@@ -1256,9 +1256,9 @@ describe('ReactOffscreen', () => {
       return (
         <>
           <Child label={'Shell ' + step} />
-          <Offscreen mode={showMore ? 'visible' : 'hidden'}>
+          <Activity mode={showMore ? 'visible' : 'hidden'}>
             <Child label={'More ' + step} />
-          </Offscreen>
+          </Activity>
         </>
       );
     }
@@ -1297,7 +1297,7 @@ describe('ReactOffscreen', () => {
   });
 
   // @gate enableOffscreen
-  it('does not mount effects when prerendering a nested Offscreen boundary', async () => {
+  it('does not mount effects when prerendering a nested Activity boundary', async () => {
     function Child({label}) {
       useEffect(() => {
         Scheduler.log('Mount ' + label);
@@ -1310,23 +1310,23 @@ describe('ReactOffscreen', () => {
 
     function App({showOuter, showInner}) {
       return (
-        <Offscreen mode={showOuter ? 'visible' : 'hidden'}>
+        <Activity mode={showOuter ? 'visible' : 'hidden'}>
           {useMemo(
             () => (
               <div>
                 <Child label="Outer" />
                 {showInner ? (
-                  <Offscreen mode="visible">
+                  <Activity mode="visible">
                     <div>
                       <Child label="Inner" />
                     </div>
-                  </Offscreen>
+                  </Activity>
                 ) : null}
               </div>
             ),
             [showInner],
           )}
-        </Offscreen>
+        </Activity>
       );
     }
 
@@ -1375,7 +1375,7 @@ describe('ReactOffscreen', () => {
   });
 
   // @gate enableOffscreen
-  it('reveal an outer Offscreen boundary without revealing an inner one', async () => {
+  it('reveal an outer Activity boundary without revealing an inner one', async () => {
     function Child({label}) {
       useEffect(() => {
         Scheduler.log('Mount ' + label);
@@ -1388,21 +1388,21 @@ describe('ReactOffscreen', () => {
 
     function App({showOuter, showInner}) {
       return (
-        <Offscreen mode={showOuter ? 'visible' : 'hidden'}>
+        <Activity mode={showOuter ? 'visible' : 'hidden'}>
           {useMemo(
             () => (
               <div>
                 <Child label="Outer" />
-                <Offscreen mode={showInner ? 'visible' : 'hidden'}>
+                <Activity mode={showInner ? 'visible' : 'hidden'}>
                   <div>
                     <Child label="Inner" />
                   </div>
-                </Offscreen>
+                </Activity>
               </div>
             ),
             [showInner],
           )}
-        </Offscreen>
+        </Activity>
       );
     }
 
@@ -1448,13 +1448,13 @@ describe('ReactOffscreen', () => {
       function App({mode}) {
         offscreenRef = useRef(null);
         return (
-          <Offscreen
+          <Activity
             mode={mode}
             ref={ref => {
               offscreenRef.current = ref;
             }}>
             <div />
-          </Offscreen>
+          </Activity>
         );
       }
 
@@ -1486,7 +1486,7 @@ describe('ReactOffscreen', () => {
     });
 
     // @gate enableOffscreen
-    it('should lower update priority for detached Offscreen', async () => {
+    it('should lower update priority for detached Activity', async () => {
       let updateChildState;
       let updateHighPriorityComponentState;
       let offscreenRef;
@@ -1515,9 +1515,9 @@ describe('ReactOffscreen', () => {
         return (
           <>
             <HighPriorityComponent>
-              <Offscreen mode={'manual'} ref={offscreenRef}>
+              <Activity mode={'manual'} ref={offscreenRef}>
                 <Child />
-              </Offscreen>
+              </Activity>
             </HighPriorityComponent>
           </>
         );
@@ -1539,7 +1539,7 @@ describe('ReactOffscreen', () => {
 
       expect(offscreenRef.current).not.toBeNull();
 
-      // Offscreen is attached by default. State updates from offscreen are **not defered**.
+      // Activity is attached by default. State updates from offscreen are **not defered**.
       await act(async () => {
         updateChildState(1);
         updateHighPriorityComponentState(1);
@@ -1556,7 +1556,7 @@ describe('ReactOffscreen', () => {
         offscreenRef.current.detach();
       });
 
-      // Offscreen is detached. State updates from offscreen are **defered**.
+      // Activity is detached. State updates from offscreen are **defered**.
       await act(async () => {
         updateChildState(2);
         updateHighPriorityComponentState(2);
@@ -1581,7 +1581,7 @@ describe('ReactOffscreen', () => {
         offscreenRef.current.attach();
       });
 
-      // Offscreen is attached. State updates from offscreen are **not defered**.
+      // Activity is attached. State updates from offscreen are **not defered**.
       await act(async () => {
         updateChildState(3);
         updateHighPriorityComponentState(3);
@@ -1640,9 +1640,9 @@ describe('ReactOffscreen', () => {
         return (
           <>
             <HighPriorityComponent>
-              <Offscreen mode={'manual'} ref={offscreenRef}>
+              <Activity mode={'manual'} ref={offscreenRef}>
                 <Child />
-              </Offscreen>
+              </Activity>
             </HighPriorityComponent>
           </>
         );
@@ -1658,7 +1658,7 @@ describe('ReactOffscreen', () => {
 
       nextRenderTriggerDetach = true;
 
-      // Offscreen is attached and gets detached inside useLayoutEffect.
+      // Activity is attached and gets detached inside useLayoutEffect.
       // State updates from offscreen are **defered**.
       await act(async () => {
         updateChildState(1);
@@ -1686,8 +1686,8 @@ describe('ReactOffscreen', () => {
 
       nextRenderTriggerAttach = true;
 
-      // Offscreen is detached. State updates from offscreen are **defered**.
-      // Offscreen is attached inside useLayoutEffect;
+      // Activity is detached. State updates from offscreen are **defered**.
+      // Activity is attached inside useLayoutEffect;
       await act(async () => {
         updateChildState(3);
         updateHighPriorityComponentState(3);
@@ -1703,19 +1703,19 @@ describe('ReactOffscreen', () => {
   });
 
   // @gate enableOffscreen
-  it('should detach ref if Offscreen is unmounted', async () => {
+  it('should detach ref if Activity is unmounted', async () => {
     let offscreenRef;
 
     function App({showOffscreen}) {
       offscreenRef = useRef(null);
       return showOffscreen ? (
-        <Offscreen
+        <Activity
           mode={'manual'}
           ref={ref => {
             offscreenRef.current = ref;
           }}>
           <div />
-        </Offscreen>
+        </Activity>
       ) : null;
     }
 
@@ -1741,17 +1741,17 @@ describe('ReactOffscreen', () => {
   });
 
   // @gate enableOffscreen
-  it('should detach ref when parent Offscreen is hidden', async () => {
+  it('should detach ref when parent Activity is hidden', async () => {
     let offscreenRef;
 
     function App({mode}) {
       offscreenRef = useRef(null);
       return (
-        <Offscreen mode={mode}>
-          <Offscreen mode={'manual'} ref={offscreenRef}>
+        <Activity mode={mode}>
+          <Activity mode={'manual'} ref={offscreenRef}>
             <div />
-          </Offscreen>
-        </Offscreen>
+          </Activity>
+        </Activity>
       );
     }
 
@@ -1783,9 +1783,9 @@ describe('ReactOffscreen', () => {
     function App({children}) {
       offscreenRef = useRef(null);
       return (
-        <Offscreen mode={'manual'} ref={offscreenRef}>
+        <Activity mode={'manual'} ref={offscreenRef}>
           {children}
-        </Offscreen>
+        </Activity>
       );
     }
 
@@ -1836,9 +1836,9 @@ describe('ReactOffscreen', () => {
 
     function App() {
       return (
-        <Offscreen mode={'manual'} ref={el => (offscreenRef = el)}>
+        <Activity mode={'manual'} ref={el => (offscreenRef = el)}>
           <Child />
-        </Offscreen>
+        </Activity>
       );
     }
 
@@ -1859,7 +1859,7 @@ describe('ReactOffscreen', () => {
     expect(spanRef.current).toBeNull();
     assertLog(['Unmount Layout Child', 'Unmount Child']);
 
-    // Calling attach on already attached Offscreen.
+    // Calling attach on already attached Activity.
     await act(() => {
       offscreenRef.detach();
     });
@@ -1873,7 +1873,7 @@ describe('ReactOffscreen', () => {
     expect(spanRef.current).not.toBeNull();
     assertLog(['Mount Layout Child', 'Mount Child']);
 
-    // Calling attach on already attached Offscreen
+    // Calling attach on already attached Activity
     offscreenRef.attach();
 
     assertLog([]);
@@ -1887,13 +1887,13 @@ describe('ReactOffscreen', () => {
     function App() {
       return (
         <LoggedText text={'outer'}>
-          <Offscreen mode={'manual'} ref={el => (outerOffscreen = el)}>
+          <Activity mode={'manual'} ref={el => (outerOffscreen = el)}>
             <LoggedText text={'middle'}>
-              <Offscreen mode={'manual'} ref={el => (innerOffscreen = el)}>
+              <Activity mode={'manual'} ref={el => (innerOffscreen = el)}>
                 <LoggedText text={'inner'} />
-              </Offscreen>
+              </Activity>
             </LoggedText>
-          </Offscreen>
+          </Activity>
         </LoggedText>
       );
     }
@@ -1949,7 +1949,7 @@ describe('ReactOffscreen', () => {
 
     assertLog(['unmount layout inner', 'unmount inner']);
 
-    // Calling detach on already detached Offscreen.
+    // Calling detach on already detached Activity.
     await act(() => {
       innerOffscreen.detach();
     });
@@ -1985,9 +1985,9 @@ describe('ReactOffscreen', () => {
     const offscreen = React.createRef(null);
     function App() {
       return (
-        <Offscreen ref={offscreen} mode="manual">
+        <Activity ref={offscreen} mode="manual">
           <Child />
-        </Offscreen>
+        </Activity>
       );
     }
 
@@ -2045,9 +2045,9 @@ describe('ReactOffscreen', () => {
         instance.attach();
       }, []);
       return (
-        <Offscreen ref={offscreen} mode="manual">
+        <Activity ref={offscreen} mode="manual">
           <Child />
-        </Offscreen>
+        </Activity>
       );
     }
 
diff --git a/packages/react-reconciler/src/__tests__/ReactOffscreenStrictMode-test.js b/packages/react-reconciler/src/__tests__/ReactOffscreenStrictMode-test.js
index a12262611761..5a1ca0158b5d 100644
--- a/packages/react-reconciler/src/__tests__/ReactOffscreenStrictMode-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactOffscreenStrictMode-test.js
@@ -1,5 +1,5 @@
 let React;
-let Offscreen;
+let Activity;
 let ReactNoop;
 let act;
 let log;
@@ -10,7 +10,7 @@ describe('ReactOffscreenStrictMode', () => {
     log = [];
 
     React = require('react');
-    Offscreen = React.unstable_Offscreen;
+    Activity = React.unstable_Activity;
     ReactNoop = require('react-noop-renderer');
     act = require('internal-test-utils').act;
   });
@@ -36,9 +36,9 @@ describe('ReactOffscreenStrictMode', () => {
     await act(() => {
       ReactNoop.render(
         <React.StrictMode>
-          <Offscreen mode="visible">
+          <Activity mode="visible">
             <Component label="A" />
-          </Offscreen>
+          </Activity>
         </React.StrictMode>,
       );
     });
@@ -60,9 +60,9 @@ describe('ReactOffscreenStrictMode', () => {
     await act(() => {
       ReactNoop.render(
         <React.StrictMode DO_NOT_USE_disableStrictPassiveEffect={true}>
-          <Offscreen>
+          <Activity>
             <Component label="A" />
-          </Offscreen>
+          </Activity>
         </React.StrictMode>,
       );
     });
@@ -82,9 +82,9 @@ describe('ReactOffscreenStrictMode', () => {
     await act(() => {
       ReactNoop.render(
         <React.StrictMode>
-          <Offscreen mode="hidden">
+          <Activity mode="hidden">
             <Component label="A" />
-          </Offscreen>
+          </Activity>
         </React.StrictMode>,
       );
     });
@@ -96,10 +96,10 @@ describe('ReactOffscreenStrictMode', () => {
     await act(() => {
       ReactNoop.render(
         <React.StrictMode>
-          <Offscreen mode="hidden">
+          <Activity mode="hidden">
             <Component label="A" />
             <Component label="B" />
-          </Offscreen>
+          </Activity>
         </React.StrictMode>,
       );
     });
@@ -111,9 +111,9 @@ describe('ReactOffscreenStrictMode', () => {
     await act(() => {
       ReactNoop.render(
         <React.StrictMode>
-          <Offscreen mode="visible">
+          <Activity mode="visible">
             <Component label="A" />
-          </Offscreen>
+          </Activity>
         </React.StrictMode>,
       );
     });
@@ -134,9 +134,9 @@ describe('ReactOffscreenStrictMode', () => {
     await act(() => {
       ReactNoop.render(
         <React.StrictMode>
-          <Offscreen mode="hidden">
+          <Activity mode="hidden">
             <Component label="A" />
-          </Offscreen>
+          </Activity>
         </React.StrictMode>,
       );
     });
@@ -218,9 +218,9 @@ describe('ReactOffscreenStrictMode', () => {
     await act(() => {
       ReactNoop.render(
         <React.StrictMode>
-          <Offscreen mode="visible">
+          <Activity mode="visible">
             <Parent />
-          </Offscreen>
+          </Activity>
         </React.StrictMode>,
       );
     });
diff --git a/packages/react-reconciler/src/__tests__/ReactOffscreenSuspense-test.js b/packages/react-reconciler/src/__tests__/ReactOffscreenSuspense-test.js
index c73e3caf62c6..b69e762452c2 100644
--- a/packages/react-reconciler/src/__tests__/ReactOffscreenSuspense-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactOffscreenSuspense-test.js
@@ -3,7 +3,7 @@ let ReactNoop;
 let Scheduler;
 let act;
 let LegacyHidden;
-let Offscreen;
+let Activity;
 let Suspense;
 let useState;
 let useEffect;
@@ -22,7 +22,7 @@ describe('ReactOffscreen', () => {
     Scheduler = require('scheduler');
     act = require('internal-test-utils').act;
     LegacyHidden = React.unstable_LegacyHidden;
-    Offscreen = React.unstable_Offscreen;
+    Activity = React.unstable_Activity;
     Suspense = React.Suspense;
     useState = React.useState;
     useEffect = React.useEffect;
@@ -108,11 +108,11 @@ describe('ReactOffscreen', () => {
           <span>
             <Text text="Visible" />
           </span>
-          <Offscreen mode="hidden">
+          <Activity mode="hidden">
             <span>
               <AsyncText text="Hidden" />
             </span>
-          </Offscreen>
+          </Activity>
         </Suspense>
       );
     }
@@ -159,7 +159,7 @@ describe('ReactOffscreen', () => {
       );
     }
 
-    // Unlike Offscreen, LegacyHidden never captures if something suspends
+    // Unlike Activity, LegacyHidden never captures if something suspends
     await act(() => {
       root.render(<App />);
     });
@@ -184,9 +184,9 @@ describe('ReactOffscreen', () => {
           <span>
             <Text text={open ? 'Open' : 'Closed'} />
           </span>
-          <Offscreen mode={open ? 'visible' : 'hidden'}>
+          <Activity mode={open ? 'visible' : 'hidden'}>
             <span>{children}</span>
-          </Offscreen>
+          </Activity>
         </Suspense>
       );
     }
@@ -243,9 +243,9 @@ describe('ReactOffscreen', () => {
           <span>
             <Text text={open ? 'Open' : 'Closed'} />
           </span>
-          <Offscreen mode={open ? 'visible' : 'hidden'}>
+          <Activity mode={open ? 'visible' : 'hidden'}>
             <span>{children}</span>
-          </Offscreen>
+          </Activity>
         </Suspense>
       );
     }
@@ -330,11 +330,11 @@ describe('ReactOffscreen', () => {
 
     function App({show}) {
       return (
-        <Offscreen mode={show ? 'visible' : 'hidden'}>
+        <Activity mode={show ? 'visible' : 'hidden'}>
           <span>
             <Child />
           </span>
-        </Offscreen>
+        </Activity>
       );
     }
 
@@ -368,11 +368,11 @@ describe('ReactOffscreen', () => {
 
     function App({show}) {
       return (
-        <Offscreen mode={show ? 'visible' : 'hidden'}>
+        <Activity mode={show ? 'visible' : 'hidden'}>
           <span>
             <Child />
           </span>
-        </Offscreen>
+        </Activity>
       );
     }
 
@@ -413,7 +413,7 @@ describe('ReactOffscreen', () => {
   test('detect updates to a hidden tree during a concurrent event', async () => {
     // This is a pretty complex test case. It relates to how we detect if an
     // update is made to a hidden tree: when scheduling the update, we walk up
-    // the fiber return path to see if any of the parents is a hidden Offscreen
+    // the fiber return path to see if any of the parents is a hidden Activity
     // component. This doesn't work if there's already a render in progress,
     // because the tree might be about to flip to hidden. To avoid a data race,
     // queue updates atomically: wait to queue the update until after the
@@ -443,11 +443,11 @@ describe('ReactOffscreen', () => {
       setOuter = _setOuter;
       return (
         <>
-          <Offscreen mode={show ? 'visible' : 'hidden'}>
+          <Activity mode={show ? 'visible' : 'hidden'}>
             <span>
               <Child outer={outer} />
             </span>
-          </Offscreen>
+          </Activity>
           <span>
             <Text text={'Outer: ' + outer} />
           </span>
diff --git a/packages/react-reconciler/src/__tests__/ReactSuspenseyCommitPhase-test.js b/packages/react-reconciler/src/__tests__/ReactSuspenseyCommitPhase-test.js
index 6112cd2f4f3a..a282912fdbcd 100644
--- a/packages/react-reconciler/src/__tests__/ReactSuspenseyCommitPhase-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactSuspenseyCommitPhase-test.js
@@ -4,7 +4,7 @@ let ReactNoop;
 let resolveSuspenseyThing;
 let getSuspenseyThingStatus;
 let Suspense;
-let Offscreen;
+let Activity;
 let SuspenseList;
 let useMemo;
 let Scheduler;
@@ -23,7 +23,7 @@ describe('ReactSuspenseyCommitPhase', () => {
     if (gate(flags => flags.enableSuspenseList)) {
       SuspenseList = React.unstable_SuspenseList;
     }
-    Offscreen = React.unstable_Offscreen;
+    Activity = React.unstable_Activity;
     useMemo = React.useMemo;
     startTransition = React.startTransition;
     resolveSuspenseyThing = ReactNoop.resolveSuspenseyThing;
@@ -206,7 +206,7 @@ describe('ReactSuspenseyCommitPhase', () => {
     // TODO: Notice that none of these items appear until they've all loaded.
     // That's not ideal; we should commit each row as it becomes ready to
     // commit. That means we need to prepare both the fallback and the primary
-    // tree during the render phase. Related to Offscreen, too.
+    // tree during the render phase. Related to Activity, too.
     resolveSuspenseyThing('A');
     expect(root).toMatchRenderedOutput('Loading ALoading BLoading C');
     resolveSuspenseyThing('B');
@@ -282,7 +282,7 @@ describe('ReactSuspenseyCommitPhase', () => {
       return (
         <>
           <div>Main Content</div>
-          <Offscreen mode={showMore ? 'visible' : 'hidden'}>{more}</Offscreen>
+          <Activity mode={showMore ? 'visible' : 'hidden'}>{more}</Activity>
         </>
       );
     }
diff --git a/packages/react-reconciler/src/__tests__/ReactTransitionTracing-test.js b/packages/react-reconciler/src/__tests__/ReactTransitionTracing-test.js
index b909ceb0e16c..72397a8446a5 100644
--- a/packages/react-reconciler/src/__tests__/ReactTransitionTracing-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactTransitionTracing-test.js
@@ -18,7 +18,7 @@ let assertLog;
 let getCacheForType;
 let useState;
 let Suspense;
-let Offscreen;
+let Activity;
 let startTransition;
 
 let caches;
@@ -52,7 +52,7 @@ describe('ReactInteractionTracing', () => {
     useState = React.useState;
     startTransition = React.startTransition;
     Suspense = React.Suspense;
-    Offscreen = React.unstable_Offscreen;
+    Activity = React.unstable_Activity;
 
     getCacheForType = React.unstable_getCacheForType;
 
@@ -2180,11 +2180,11 @@ describe('ReactInteractionTracing', () => {
           <Suspense fallback={<Text text="Loading..." />}>
             <AsyncText text="Text" />
           </Suspense>
-          <Offscreen mode="hidden">
+          <Activity mode="hidden">
             <Suspense fallback={<Text text="Hidden Loading..." />}>
               <AsyncText text="Hidden Text" />
             </Suspense>
-          </Offscreen>
+          </Activity>
         </React.unstable_TracingMarker>
       );
     }
diff --git a/packages/react/index.classic.fb.js b/packages/react/index.classic.fb.js
index f096b478708d..035e5c0aec2d 100644
--- a/packages/react/index.classic.fb.js
+++ b/packages/react/index.classic.fb.js
@@ -29,11 +29,11 @@ export {
   memo,
   cache,
   startTransition,
+  unstable_Activity,
   unstable_Cache,
   unstable_TracingMarker,
   unstable_DebugTracingMode,
   unstable_LegacyHidden,
-  unstable_Offscreen,
   unstable_Scope,
   unstable_SuspenseList,
   unstable_getCacheSignal,
diff --git a/packages/react/index.experimental.js b/packages/react/index.experimental.js
index c3d7e01adb6b..bdb26a4c4207 100644
--- a/packages/react/index.experimental.js
+++ b/packages/react/index.experimental.js
@@ -32,7 +32,7 @@ export {
   startTransition,
   unstable_Cache,
   unstable_DebugTracingMode,
-  unstable_Offscreen,
+  unstable_Activity,
   unstable_postpone,
   unstable_getCacheSignal,
   unstable_getCacheForType,
diff --git a/packages/react/index.js b/packages/react/index.js
index 9ba3d9402c42..bef926da87e5 100644
--- a/packages/react/index.js
+++ b/packages/react/index.js
@@ -56,7 +56,7 @@ export {
   unstable_Cache,
   unstable_DebugTracingMode,
   unstable_LegacyHidden,
-  unstable_Offscreen,
+  unstable_Activity,
   unstable_Scope,
   unstable_SuspenseList,
   unstable_TracingMarker,
diff --git a/packages/react/index.modern.fb.js b/packages/react/index.modern.fb.js
index 601c4eebca4a..1ef63b605af3 100644
--- a/packages/react/index.modern.fb.js
+++ b/packages/react/index.modern.fb.js
@@ -31,7 +31,7 @@ export {
   unstable_Cache,
   unstable_DebugTracingMode,
   unstable_LegacyHidden,
-  unstable_Offscreen,
+  unstable_Activity,
   unstable_Scope,
   unstable_SuspenseList,
   unstable_getCacheSignal,
diff --git a/packages/react/src/React.js b/packages/react/src/React.js
index 3e9a869623a3..5728a2ba50d7 100644
--- a/packages/react/src/React.js
+++ b/packages/react/src/React.js
@@ -134,7 +134,7 @@ export {
   useDeferredValue,
   REACT_SUSPENSE_LIST_TYPE as unstable_SuspenseList,
   REACT_LEGACY_HIDDEN_TYPE as unstable_LegacyHidden,
-  REACT_OFFSCREEN_TYPE as unstable_Offscreen,
+  REACT_OFFSCREEN_TYPE as unstable_Activity,
   getCacheSignal as unstable_getCacheSignal,
   getCacheForType as unstable_getCacheForType,
   useCacheRefresh as unstable_useCacheRefresh,

From 9cc468e368ede9cdd4345606d97ecfadf1a759ae Mon Sep 17 00:00:00 2001
From: Jan Kassens <jkassens@meta.com>
Date: Thu, 2 Nov 2023 13:58:21 -0400
Subject: [PATCH 2/3] rename enableOffscreen to enableActivity

---
 ...DOMServerPartialHydration-test.internal.js |  4 +-
 .../src/__tests__/ReactCache-test.js          |  2 +-
 .../src/__tests__/ReactDeferredValue-test.js  | 10 ++--
 .../src/__tests__/ReactOffscreen-test.js      | 58 +++++++++----------
 .../ReactOffscreenStrictMode-test.js          |  8 +--
 .../__tests__/ReactOffscreenSuspense-test.js  |  6 +-
 .../ReactSuspenseyCommitPhase-test.js         |  2 +-
 scripts/jest/TestFlags.js                     |  2 +-
 8 files changed, 46 insertions(+), 46 deletions(-)

diff --git a/packages/react-dom/src/__tests__/ReactDOMServerPartialHydration-test.internal.js b/packages/react-dom/src/__tests__/ReactDOMServerPartialHydration-test.internal.js
index 9d9f35eb01c2..f373213b099b 100644
--- a/packages/react-dom/src/__tests__/ReactDOMServerPartialHydration-test.internal.js
+++ b/packages/react-dom/src/__tests__/ReactDOMServerPartialHydration-test.internal.js
@@ -3151,7 +3151,7 @@ describe('ReactDOMServerPartialHydration', () => {
     expect(ref.current.innerHTML).toBe('Hidden child');
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('a visible Activity component acts like a fragment', async () => {
     const ref = React.createRef();
 
@@ -3187,7 +3187,7 @@ describe('ReactDOMServerPartialHydration', () => {
     expect(ref.current).toBe(span);
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('a hidden Activity component is skipped over during server rendering', async () => {
     const visibleRef = React.createRef();
 
diff --git a/packages/react-reconciler/src/__tests__/ReactCache-test.js b/packages/react-reconciler/src/__tests__/ReactCache-test.js
index 83d7f0b69760..dd4a7c5d5fd1 100644
--- a/packages/react-reconciler/src/__tests__/ReactCache-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactCache-test.js
@@ -1576,7 +1576,7 @@ describe('ReactCache', () => {
     expect(root).toMatchRenderedOutput('Bye!');
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   // @gate enableCache
   test('prerender a new cache boundary inside an Activity tree', async () => {
     function App({prerenderMore}) {
diff --git a/packages/react-reconciler/src/__tests__/ReactDeferredValue-test.js b/packages/react-reconciler/src/__tests__/ReactDeferredValue-test.js
index b34bc80a18f7..22f2d33f3396 100644
--- a/packages/react-reconciler/src/__tests__/ReactDeferredValue-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactDeferredValue-test.js
@@ -569,7 +569,7 @@ describe('ReactDeferredValue', () => {
   });
 
   // @gate enableUseDeferredValueInitialArg
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('useDeferredValue can spawn a deferred task while prerendering a hidden tree', async () => {
     function App() {
       const text = useDeferredValue('Final', 'Preview');
@@ -616,7 +616,7 @@ describe('ReactDeferredValue', () => {
   });
 
   // @gate enableUseDeferredValueInitialArg
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('useDeferredValue can prerender the initial value inside a hidden tree', async () => {
     function App({text}) {
       const renderedText = useDeferredValue(text, `Preview [${text}]`);
@@ -675,7 +675,7 @@ describe('ReactDeferredValue', () => {
   });
 
   // @gate enableUseDeferredValueInitialArg
-  // @gate enableOffscreen
+  // @gate enableActivity
   it(
     'useDeferredValue skips the preview state when revealing a hidden tree ' +
       'if the final value is referentially identical',
@@ -716,7 +716,7 @@ describe('ReactDeferredValue', () => {
   );
 
   // @gate enableUseDeferredValueInitialArg
-  // @gate enableOffscreen
+  // @gate enableActivity
   it(
     'useDeferredValue does not skip the preview state when revealing a ' +
       'hidden tree if the final value is different from the currently rendered one',
@@ -761,7 +761,7 @@ describe('ReactDeferredValue', () => {
     },
   );
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it(
     'useDeferredValue does not show "previous" value when revealing a hidden ' +
       'tree (no initial value)',
diff --git a/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js b/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js
index dabc562c97c9..86eb99d687fe 100644
--- a/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js
@@ -209,7 +209,7 @@ describe('ReactOffscreen', () => {
     );
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('mounts without layout effects when hidden', async () => {
     function Child({text}) {
       useLayoutEffect(() => {
@@ -247,7 +247,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span prop="Child" />);
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('mounts/unmounts layout effects when visibility changes (starting visible)', async () => {
     function Child({text}) {
       useLayoutEffect(() => {
@@ -293,7 +293,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span prop="Child" />);
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('nested offscreen does not call componentWillUnmount when hidden', async () => {
     // This is a bug that appeared during production test of <unstable_Activity />.
     // It is a very specific scenario with nested Offscreens. The inner offscreen
@@ -397,7 +397,7 @@ describe('ReactOffscreen', () => {
     assertLog(['child']);
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('mounts/unmounts layout effects when visibility changes (starting hidden)', async () => {
     function Child({text}) {
       useLayoutEffect(() => {
@@ -444,7 +444,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span hidden={true} prop="Child" />);
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('hides children of offscreen after layout effects are destroyed', async () => {
     const root = ReactNoop.createRoot();
     function Child({text}) {
@@ -531,7 +531,7 @@ describe('ReactOffscreen', () => {
     assertLog(['Unmount layout']);
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('hides new insertions into an already hidden tree', async () => {
     const root = ReactNoop.createRoot();
     await act(() => {
@@ -561,7 +561,7 @@ describe('ReactOffscreen', () => {
     );
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('hides updated nodes inside an already hidden tree', async () => {
     const root = ReactNoop.createRoot();
     await act(() => {
@@ -607,7 +607,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span>Hi</span>);
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('revealing a hidden tree at high priority does not cause tearing', async () => {
     // When revealing an offscreen tree, we need to include updates that were
     // previously deferred because the tree was hidden, even if they are lower
@@ -741,7 +741,7 @@ describe('ReactOffscreen', () => {
     expect(areOuterAndInnerConsistent()).toBe(true);
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('regression: Activity instance is sometimes null during setState', async () => {
     let setState;
     function Child() {
@@ -789,7 +789,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(null);
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('class component setState callbacks do not fire until tree is visible', async () => {
     const root = ReactNoop.createRoot();
 
@@ -841,7 +841,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span prop="C" />);
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('does not call componentDidUpdate when reappearing a hidden class component', async () => {
     class Child extends React.Component {
       componentDidMount() {
@@ -891,7 +891,7 @@ describe('ReactOffscreen', () => {
     assertLog(['componentDidMount']);
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it(
     'when reusing old components (hidden -> visible), layout effects fire ' +
       'with same timing as if it were brand new',
@@ -944,7 +944,7 @@ describe('ReactOffscreen', () => {
     },
   );
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it(
     'when reusing old components (hidden -> visible), layout effects fire ' +
       'with same timing as if it were brand new (includes setState callback)',
@@ -1007,7 +1007,7 @@ describe('ReactOffscreen', () => {
     },
   );
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('defer passive effects when prerendering a new Activity tree', async () => {
     function Child({label}) {
       useEffect(() => {
@@ -1125,7 +1125,7 @@ describe('ReactOffscreen', () => {
     assertLog(['Shell', 'More']);
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('passive effects are connected and disconnected when the visibility changes', async () => {
     function Child({step}) {
       useEffect(() => {
@@ -1182,7 +1182,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span prop={2} />);
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('passive effects are unmounted on hide in the same order as during a deletion: parent before child', async () => {
     function Child({label}) {
       useEffect(() => {
@@ -1240,7 +1240,7 @@ describe('ReactOffscreen', () => {
   // Re-enable this test once we add this ability. For example, we'll likely add
   // either an option or a heuristic to mount passive effects inside a hidden
   // tree after a delay.
-  // @gate enableOffscreen
+  // @gate enableActivity
   it.skip("don't defer passive effects when prerendering in a tree whose effects are already connected", async () => {
     function Child({label}) {
       useEffect(() => {
@@ -1296,7 +1296,7 @@ describe('ReactOffscreen', () => {
     ]);
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('does not mount effects when prerendering a nested Activity boundary', async () => {
     function Child({label}) {
       useEffect(() => {
@@ -1374,7 +1374,7 @@ describe('ReactOffscreen', () => {
     );
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('reveal an outer Activity boundary without revealing an inner one', async () => {
     function Child({label}) {
       useEffect(() => {
@@ -1441,7 +1441,7 @@ describe('ReactOffscreen', () => {
   });
 
   describe('manual interactivity', () => {
-    // @gate enableOffscreen
+    // @gate enableActivity
     it('should attach ref only for mode null', async () => {
       let offscreenRef;
 
@@ -1485,7 +1485,7 @@ describe('ReactOffscreen', () => {
       expect(offscreenRef.current).not.toBeNull();
     });
 
-    // @gate enableOffscreen
+    // @gate enableActivity
     it('should lower update priority for detached Activity', async () => {
       let updateChildState;
       let updateHighPriorityComponentState;
@@ -1595,7 +1595,7 @@ describe('ReactOffscreen', () => {
       });
     });
 
-    // @gate enableOffscreen
+    // @gate enableActivity
     it('defers detachment if called during commit', async () => {
       let updateChildState;
       let updateHighPriorityComponentState;
@@ -1702,7 +1702,7 @@ describe('ReactOffscreen', () => {
     });
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('should detach ref if Activity is unmounted', async () => {
     let offscreenRef;
 
@@ -1740,7 +1740,7 @@ describe('ReactOffscreen', () => {
     expect(offscreenRef.current).not.toBeNull();
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('should detach ref when parent Activity is hidden', async () => {
     let offscreenRef;
 
@@ -1775,7 +1775,7 @@ describe('ReactOffscreen', () => {
     expect(offscreenRef.current).toBeNull();
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('should change _current', async () => {
     let offscreenRef;
     const root = ReactNoop.createRoot();
@@ -1811,7 +1811,7 @@ describe('ReactOffscreen', () => {
     expect(offscreenRef.current._current === firstFiber).toBeFalsy();
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('does not mount tree until attach is called', async () => {
     let offscreenRef;
     let spanRef;
@@ -1879,7 +1879,7 @@ describe('ReactOffscreen', () => {
     assertLog([]);
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('handles nested manual offscreens', async () => {
     let outerOffscreen;
     let innerOffscreen;
@@ -1970,7 +1970,7 @@ describe('ReactOffscreen', () => {
     assertLog(['unmount layout inner', 'unmount inner']);
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('batches multiple attach and detach calls scheduled from an event handler', async () => {
     function Child() {
       useEffect(() => {
@@ -2024,7 +2024,7 @@ describe('ReactOffscreen', () => {
     assertLog([]);
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   it('batches multiple attach and detach calls scheduled from an effect', async () => {
     function Child() {
       useEffect(() => {
diff --git a/packages/react-reconciler/src/__tests__/ReactOffscreenStrictMode-test.js b/packages/react-reconciler/src/__tests__/ReactOffscreenStrictMode-test.js
index 5a1ca0158b5d..438a4de62abd 100644
--- a/packages/react-reconciler/src/__tests__/ReactOffscreenStrictMode-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactOffscreenStrictMode-test.js
@@ -31,7 +31,7 @@ describe('ReactOffscreenStrictMode', () => {
     return <span>label</span>;
   }
 
-  // @gate __DEV__ && enableOffscreen
+  // @gate __DEV__ && enableActivity
   it('should trigger strict effects when offscreen is visible', async () => {
     await act(() => {
       ReactNoop.render(
@@ -55,7 +55,7 @@ describe('ReactOffscreenStrictMode', () => {
     ]);
   });
 
-  // @gate __DEV__ && enableOffscreen && enableDO_NOT_USE_disableStrictPassiveEffect
+  // @gate __DEV__ && enableActivity && enableDO_NOT_USE_disableStrictPassiveEffect
   it('does not trigger strict effects when disableStrictPassiveEffect is presented on StrictMode', async () => {
     await act(() => {
       ReactNoop.render(
@@ -77,7 +77,7 @@ describe('ReactOffscreenStrictMode', () => {
     ]);
   });
 
-  // @gate __DEV__ && enableOffscreen && useModernStrictMode
+  // @gate __DEV__ && enableActivity && useModernStrictMode
   it('should not trigger strict effects when offscreen is hidden', async () => {
     await act(() => {
       ReactNoop.render(
@@ -176,7 +176,7 @@ describe('ReactOffscreenStrictMode', () => {
     });
   });
 
-  // @gate __DEV__ && enableOffscreen
+  // @gate __DEV__ && enableActivity
   it('should double invoke effects on unsuspended child', async () => {
     let shouldSuspend = true;
     let resolve;
diff --git a/packages/react-reconciler/src/__tests__/ReactOffscreenSuspense-test.js b/packages/react-reconciler/src/__tests__/ReactOffscreenSuspense-test.js
index b69e762452c2..35365a932f49 100644
--- a/packages/react-reconciler/src/__tests__/ReactOffscreenSuspense-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactOffscreenSuspense-test.js
@@ -98,7 +98,7 @@ describe('ReactOffscreen', () => {
     return text;
   }
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   test('basic example of suspending inside hidden tree', async () => {
     const root = ReactNoop.createRoot();
 
@@ -233,7 +233,7 @@ describe('ReactOffscreen', () => {
     );
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   test("suspending inside currently visible tree that's switching to hidden", async () => {
     const root = ReactNoop.createRoot();
 
@@ -409,7 +409,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span hidden={true}>B1</span>);
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   test('detect updates to a hidden tree during a concurrent event', async () => {
     // This is a pretty complex test case. It relates to how we detect if an
     // update is made to a hidden tree: when scheduling the update, we walk up
diff --git a/packages/react-reconciler/src/__tests__/ReactSuspenseyCommitPhase-test.js b/packages/react-reconciler/src/__tests__/ReactSuspenseyCommitPhase-test.js
index a282912fdbcd..52fd9ef3f27d 100644
--- a/packages/react-reconciler/src/__tests__/ReactSuspenseyCommitPhase-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactSuspenseyCommitPhase-test.js
@@ -269,7 +269,7 @@ describe('ReactSuspenseyCommitPhase', () => {
     );
   });
 
-  // @gate enableOffscreen
+  // @gate enableActivity
   test("host instances don't suspend during prerendering, but do suspend when they are revealed", async () => {
     function More() {
       Scheduler.log('More');
diff --git a/scripts/jest/TestFlags.js b/scripts/jest/TestFlags.js
index e919aec5ffc9..78908d91eb16 100644
--- a/scripts/jest/TestFlags.js
+++ b/scripts/jest/TestFlags.js
@@ -82,9 +82,9 @@ function getTestFlags() {
       www,
 
       // This isn't a flag, just a useful alias for tests.
+      enableActivity: releaseChannel === 'experimental' || www,
       enableUseSyncExternalStoreShim: !__VARIANT__,
       enableSuspenseList: releaseChannel === 'experimental' || www,
-      enableOffscreen: releaseChannel === 'experimental' || www,
       enableLegacyHidden: www,
 
       // If there's a naming conflict between scheduler and React feature flags, the

From 9f6a8bf5deb9ab18c6fa0ec5b5d2efbc6eeaa9d4 Mon Sep 17 00:00:00 2001
From: Jan Kassens <jkassens@meta.com>
Date: Thu, 2 Nov 2023 14:28:15 -0400
Subject: [PATCH 3/3] Update file names from Offscreen to Activity

---
 packages/react-reconciler/src/ReactFiber.js               | 4 ++--
 ...fscreenComponent.js => ReactFiberActivityComponent.js} | 0
 packages/react-reconciler/src/ReactFiberBeginWork.js      | 4 ++--
 packages/react-reconciler/src/ReactFiberCommitWork.js     | 6 +++---
 packages/react-reconciler/src/ReactFiberCompleteWork.js   | 8 +++++---
 .../react-reconciler/src/ReactFiberConcurrentUpdates.js   | 4 ++--
 .../react-reconciler/src/ReactFiberSuspenseContext.js     | 2 +-
 packages/react-reconciler/src/ReactFiberThrow.js          | 2 +-
 .../src/ReactFiberTracingMarkerComponent.js               | 2 +-
 packages/react-reconciler/src/ReactFiberWorkLoop.js       | 2 +-
 .../{ReactOffscreen-test.js => Activity-test.js}          | 2 +-
 ...creenStrictMode-test.js => ActivityStrictMode-test.js} | 2 +-
 ...OffscreenSuspense-test.js => ActivitySuspense-test.js} | 2 +-
 13 files changed, 21 insertions(+), 19 deletions(-)
 rename packages/react-reconciler/src/{ReactFiberOffscreenComponent.js => ReactFiberActivityComponent.js} (100%)
 rename packages/react-reconciler/src/__tests__/{ReactOffscreen-test.js => Activity-test.js} (99%)
 rename packages/react-reconciler/src/__tests__/{ReactOffscreenStrictMode-test.js => ActivityStrictMode-test.js} (99%)
 rename packages/react-reconciler/src/__tests__/{ReactOffscreenSuspense-test.js => ActivitySuspense-test.js} (99%)

diff --git a/packages/react-reconciler/src/ReactFiber.js b/packages/react-reconciler/src/ReactFiber.js
index c9af059d20de..de626f2b72f6 100644
--- a/packages/react-reconciler/src/ReactFiber.js
+++ b/packages/react-reconciler/src/ReactFiber.js
@@ -18,7 +18,7 @@ import type {SuspenseInstance} from './ReactFiberConfig';
 import type {
   OffscreenProps,
   OffscreenInstance,
-} from './ReactFiberOffscreenComponent';
+} from './ReactFiberActivityComponent';
 import type {TracingMarkerInstance} from './ReactFiberTracingMarkerComponent';
 
 import {
@@ -71,7 +71,7 @@ import {
   CacheComponent,
   TracingMarkerComponent,
 } from './ReactWorkTags';
-import {OffscreenVisible} from './ReactFiberOffscreenComponent';
+import {OffscreenVisible} from './ReactFiberActivityComponent';
 import getComponentNameFromFiber from 'react-reconciler/src/getComponentNameFromFiber';
 import {isDevToolsPresent} from './ReactFiberDevToolsHook';
 import {
diff --git a/packages/react-reconciler/src/ReactFiberOffscreenComponent.js b/packages/react-reconciler/src/ReactFiberActivityComponent.js
similarity index 100%
rename from packages/react-reconciler/src/ReactFiberOffscreenComponent.js
rename to packages/react-reconciler/src/ReactFiberActivityComponent.js
diff --git a/packages/react-reconciler/src/ReactFiberBeginWork.js b/packages/react-reconciler/src/ReactFiberBeginWork.js
index 621df8b78df7..7d9ddba40625 100644
--- a/packages/react-reconciler/src/ReactFiberBeginWork.js
+++ b/packages/react-reconciler/src/ReactFiberBeginWork.js
@@ -27,8 +27,8 @@ import type {
   OffscreenState,
   OffscreenQueue,
   OffscreenInstance,
-} from './ReactFiberOffscreenComponent';
-import {OffscreenDetached} from './ReactFiberOffscreenComponent';
+} from './ReactFiberActivityComponent';
+import {OffscreenDetached} from './ReactFiberActivityComponent';
 import type {
   Cache,
   CacheComponentState,
diff --git a/packages/react-reconciler/src/ReactFiberCommitWork.js b/packages/react-reconciler/src/ReactFiberCommitWork.js
index 73889d8b8180..79cd32c4e42a 100644
--- a/packages/react-reconciler/src/ReactFiberCommitWork.js
+++ b/packages/react-reconciler/src/ReactFiberCommitWork.js
@@ -23,13 +23,13 @@ import type {SuspenseState, RetryQueue} from './ReactFiberSuspenseComponent';
 import type {UpdateQueue} from './ReactFiberClassUpdateQueue';
 import type {FunctionComponentUpdateQueue} from './ReactFiberHooks';
 import type {Wakeable} from 'shared/ReactTypes';
-import {isOffscreenManual} from './ReactFiberOffscreenComponent';
+import {isOffscreenManual} from './ReactFiberActivityComponent';
 import type {
   OffscreenState,
   OffscreenInstance,
   OffscreenQueue,
   OffscreenProps,
-} from './ReactFiberOffscreenComponent';
+} from './ReactFiberActivityComponent';
 import type {HookFlags} from './ReactHookEffectTags';
 import type {Cache} from './ReactFiberCacheComponent';
 import type {RootState} from './ReactFiberRoot';
@@ -209,7 +209,7 @@ import {
   OffscreenVisible,
   OffscreenDetached,
   OffscreenPassiveEffectsConnected,
-} from './ReactFiberOffscreenComponent';
+} from './ReactFiberActivityComponent';
 import {
   TransitionRoot,
   TransitionTracingMarker,
diff --git a/packages/react-reconciler/src/ReactFiberCompleteWork.js b/packages/react-reconciler/src/ReactFiberCompleteWork.js
index ecd129bbb391..575f220039f5 100644
--- a/packages/react-reconciler/src/ReactFiberCompleteWork.js
+++ b/packages/react-reconciler/src/ReactFiberCompleteWork.js
@@ -24,9 +24,11 @@ import type {
   SuspenseListRenderState,
   RetryQueue,
 } from './ReactFiberSuspenseComponent';
-import type {OffscreenQueue} from './ReactFiberOffscreenComponent';
-import {isOffscreenManual} from './ReactFiberOffscreenComponent';
-import type {OffscreenState} from './ReactFiberOffscreenComponent';
+import type {
+  OffscreenState,
+  OffscreenQueue,
+} from './ReactFiberActivityComponent';
+import {isOffscreenManual} from './ReactFiberActivityComponent';
 import type {TracingMarkerInstance} from './ReactFiberTracingMarkerComponent';
 import type {Cache} from './ReactFiberCacheComponent';
 import {
diff --git a/packages/react-reconciler/src/ReactFiberConcurrentUpdates.js b/packages/react-reconciler/src/ReactFiberConcurrentUpdates.js
index faf1664beb9b..5413db10f6f7 100644
--- a/packages/react-reconciler/src/ReactFiberConcurrentUpdates.js
+++ b/packages/react-reconciler/src/ReactFiberConcurrentUpdates.js
@@ -17,7 +17,7 @@ import type {
   Update as ClassUpdate,
 } from './ReactFiberClassUpdateQueue';
 import type {Lane, Lanes} from './ReactFiberLane';
-import type {OffscreenInstance} from './ReactFiberOffscreenComponent';
+import type {OffscreenInstance} from './ReactFiberActivityComponent';
 
 import {
   warnAboutUpdateOnNotYetMountedFiberInDEV,
@@ -27,7 +27,7 @@ import {
 import {NoLane, NoLanes, mergeLanes, markHiddenUpdate} from './ReactFiberLane';
 import {NoFlags, Placement, Hydrating} from './ReactFiberFlags';
 import {HostRoot, OffscreenComponent} from './ReactWorkTags';
-import {OffscreenVisible} from './ReactFiberOffscreenComponent';
+import {OffscreenVisible} from './ReactFiberActivityComponent';
 
 export type ConcurrentUpdate = {
   next: ConcurrentUpdate,
diff --git a/packages/react-reconciler/src/ReactFiberSuspenseContext.js b/packages/react-reconciler/src/ReactFiberSuspenseContext.js
index 05850f92df58..a03b45356a1f 100644
--- a/packages/react-reconciler/src/ReactFiberSuspenseContext.js
+++ b/packages/react-reconciler/src/ReactFiberSuspenseContext.js
@@ -10,7 +10,7 @@
 import type {Fiber} from './ReactInternalTypes';
 import type {StackCursor} from './ReactFiberStack';
 import type {SuspenseProps, SuspenseState} from './ReactFiberSuspenseComponent';
-import type {OffscreenState} from './ReactFiberOffscreenComponent';
+import type {OffscreenState} from './ReactFiberActivityComponent';
 
 import {enableSuspenseAvoidThisFallback} from 'shared/ReactFeatureFlags';
 import {createCursor, push, pop} from './ReactFiberStack';
diff --git a/packages/react-reconciler/src/ReactFiberThrow.js b/packages/react-reconciler/src/ReactFiberThrow.js
index b979f194652d..789be43b88f3 100644
--- a/packages/react-reconciler/src/ReactFiberThrow.js
+++ b/packages/react-reconciler/src/ReactFiberThrow.js
@@ -12,7 +12,7 @@ import type {Lane, Lanes} from './ReactFiberLane';
 import type {CapturedValue} from './ReactCapturedValue';
 import type {Update} from './ReactFiberClassUpdateQueue';
 import type {Wakeable} from 'shared/ReactTypes';
-import type {OffscreenQueue} from './ReactFiberOffscreenComponent';
+import type {OffscreenQueue} from './ReactFiberActivityComponent';
 import type {RetryQueue} from './ReactFiberSuspenseComponent';
 
 import getComponentNameFromFiber from 'react-reconciler/src/getComponentNameFromFiber';
diff --git a/packages/react-reconciler/src/ReactFiberTracingMarkerComponent.js b/packages/react-reconciler/src/ReactFiberTracingMarkerComponent.js
index c5817618aaf7..389325f46516 100644
--- a/packages/react-reconciler/src/ReactFiberTracingMarkerComponent.js
+++ b/packages/react-reconciler/src/ReactFiberTracingMarkerComponent.js
@@ -12,7 +12,7 @@ import type {
   Fiber,
   FiberRoot,
 } from './ReactInternalTypes';
-import type {OffscreenInstance} from './ReactFiberOffscreenComponent';
+import type {OffscreenInstance} from './ReactFiberActivityComponent';
 import type {StackCursor} from './ReactFiberStack';
 
 import {enableTransitionTracing} from 'shared/ReactFeatureFlags';
diff --git a/packages/react-reconciler/src/ReactFiberWorkLoop.js b/packages/react-reconciler/src/ReactFiberWorkLoop.js
index 2473050cf51d..54a4a122eab9 100644
--- a/packages/react-reconciler/src/ReactFiberWorkLoop.js
+++ b/packages/react-reconciler/src/ReactFiberWorkLoop.js
@@ -21,7 +21,7 @@ import type {
   Transition,
   TransitionAbort,
 } from './ReactFiberTracingMarkerComponent';
-import type {OffscreenInstance} from './ReactFiberOffscreenComponent';
+import type {OffscreenInstance} from './ReactFiberActivityComponent';
 import type {RenderTaskFn} from './ReactFiberRootScheduler';
 
 import {
diff --git a/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js b/packages/react-reconciler/src/__tests__/Activity-test.js
similarity index 99%
rename from packages/react-reconciler/src/__tests__/ReactOffscreen-test.js
rename to packages/react-reconciler/src/__tests__/Activity-test.js
index 86eb99d687fe..fc6a8b563d19 100644
--- a/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js
+++ b/packages/react-reconciler/src/__tests__/Activity-test.js
@@ -14,7 +14,7 @@ let waitForPaint;
 let waitFor;
 let assertLog;
 
-describe('ReactOffscreen', () => {
+describe('Activity', () => {
   beforeEach(() => {
     jest.resetModules();
 
diff --git a/packages/react-reconciler/src/__tests__/ReactOffscreenStrictMode-test.js b/packages/react-reconciler/src/__tests__/ActivityStrictMode-test.js
similarity index 99%
rename from packages/react-reconciler/src/__tests__/ReactOffscreenStrictMode-test.js
rename to packages/react-reconciler/src/__tests__/ActivityStrictMode-test.js
index 438a4de62abd..a8b8d286dc6a 100644
--- a/packages/react-reconciler/src/__tests__/ReactOffscreenStrictMode-test.js
+++ b/packages/react-reconciler/src/__tests__/ActivityStrictMode-test.js
@@ -4,7 +4,7 @@ let ReactNoop;
 let act;
 let log;
 
-describe('ReactOffscreenStrictMode', () => {
+describe('Activity StrictMode', () => {
   beforeEach(() => {
     jest.resetModules();
     log = [];
diff --git a/packages/react-reconciler/src/__tests__/ReactOffscreenSuspense-test.js b/packages/react-reconciler/src/__tests__/ActivitySuspense-test.js
similarity index 99%
rename from packages/react-reconciler/src/__tests__/ReactOffscreenSuspense-test.js
rename to packages/react-reconciler/src/__tests__/ActivitySuspense-test.js
index 35365a932f49..a2b4de2e0ce5 100644
--- a/packages/react-reconciler/src/__tests__/ReactOffscreenSuspense-test.js
+++ b/packages/react-reconciler/src/__tests__/ActivitySuspense-test.js
@@ -13,7 +13,7 @@ let waitFor;
 let waitForPaint;
 let assertLog;
 
-describe('ReactOffscreen', () => {
+describe('Activity Suspense', () => {
   beforeEach(() => {
     jest.resetModules();