diff --git a/src/libraries/Microsoft.Extensions.Logging.Abstractions/ref/Microsoft.Extensions.Logging.Abstractions.cs b/src/libraries/Microsoft.Extensions.Logging.Abstractions/ref/Microsoft.Extensions.Logging.Abstractions.cs
index 34f8935ac470cd..9b833bb16a4ce0 100644
--- a/src/libraries/Microsoft.Extensions.Logging.Abstractions/ref/Microsoft.Extensions.Logging.Abstractions.cs
+++ b/src/libraries/Microsoft.Extensions.Logging.Abstractions/ref/Microsoft.Extensions.Logging.Abstractions.cs
@@ -226,3 +226,45 @@ public interface IBufferedLogger
         void LogRecords(System.Collections.Generic.IEnumerable<Microsoft.Extensions.Logging.Abstractions.BufferedLogRecord> records);
     }
 }
+namespace Microsoft.Extensions.Logging.Abstractions.Internal
+{
+    [System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Never)]
+    [System.ObsoleteAttribute("This type is retained only for compatibility.", error: true)]
+    public partial class NullScope : System.IDisposable
+    {
+        private NullScope() { }
+        public static Microsoft.Extensions.Logging.Abstractions.Internal.NullScope Instance { get { throw null; } }
+        public void Dispose() { }
+    }
+    [System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Never)]
+    [System.ObsoleteAttribute("This type is retained only for compatibility.", error: true)]
+    public partial class TypeNameHelper
+    {
+        public static string GetTypeDisplayName(System.Type type) { throw null; }
+    }
+}
+namespace Microsoft.Extensions.Logging.Internal
+{
+    [System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Never)]
+    [System.ObsoleteAttribute("This type is retained only for compatibility. The recommended alternative is the Microsoft.Extensions.Diagnostics.Testing package.", error: true)]
+    public partial class FormattedLogValues : System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string, object?>>, System.Collections.Generic.IReadOnlyCollection<System.Collections.Generic.KeyValuePair<string, object?>>, System.Collections.Generic.IReadOnlyList<System.Collections.Generic.KeyValuePair<string, object?>>, System.Collections.IEnumerable
+    {
+        public FormattedLogValues(string? format, params object?[]? values) { }
+        public int Count { get { throw null; } }
+        public System.Collections.Generic.KeyValuePair<string, object?> this[int index] { get { throw null; } }
+        public System.Collections.Generic.IEnumerator<System.Collections.Generic.KeyValuePair<string, object?>> GetEnumerator() { throw null; }
+        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() { throw null; }
+        public override string ToString() { throw null; }
+    }
+    [System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Never)]
+    [System.ObsoleteAttribute("This type is retained only for compatibility. The recommended alternative is the Microsoft.Extensions.Diagnostics.Testing package.", error: true)]
+    public partial class LogValuesFormatter
+    {
+        public LogValuesFormatter(string format) { }
+        public string OriginalFormat { get { throw null; } }
+        public System.Collections.Generic.List<string> ValueNames { get { throw null; } }
+        public string Format(object?[]? values) { throw null; }
+        public System.Collections.Generic.KeyValuePair<string, object?> GetValue(object?[] values, int index) { throw null; }
+        public System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string, object?>> GetValues(object[] values) { throw null; }
+    }
+}
diff --git a/src/libraries/Microsoft.Extensions.Logging.Abstractions/ref/Microsoft.Extensions.Logging.Abstractions.csproj b/src/libraries/Microsoft.Extensions.Logging.Abstractions/ref/Microsoft.Extensions.Logging.Abstractions.csproj
index 19f520bbca8999..68eb86172fedb3 100644
--- a/src/libraries/Microsoft.Extensions.Logging.Abstractions/ref/Microsoft.Extensions.Logging.Abstractions.csproj
+++ b/src/libraries/Microsoft.Extensions.Logging.Abstractions/ref/Microsoft.Extensions.Logging.Abstractions.csproj
@@ -14,6 +14,7 @@
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == '$(NetCoreAppCurrent)'">
+    <ProjectReference Include="$(LibrariesProjectRoot)System.Collections\ref\System.Collections.csproj" />
     <ProjectReference Include="$(LibrariesProjectRoot)System.Runtime\ref\System.Runtime.csproj" />
   </ItemGroup>
 
diff --git a/src/libraries/Microsoft.Extensions.Logging.Abstractions/src/FormattedLogValuesObsolete.cs b/src/libraries/Microsoft.Extensions.Logging.Abstractions/src/FormattedLogValuesObsolete.cs
new file mode 100644
index 00000000000000..179e251bb9de91
--- /dev/null
+++ b/src/libraries/Microsoft.Extensions.Logging.Abstractions/src/FormattedLogValuesObsolete.cs
@@ -0,0 +1,46 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.ComponentModel;
+
+namespace Microsoft.Extensions.Logging.Internal
+{
+    /// <summary>
+    /// LogValues to enable formatting options supported by <see cref="string.Format(IFormatProvider, string, object?)"/>.
+    /// This also enables using {NamedFormatItem} in the format string.
+    /// </summary>
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    [Obsolete("This type is retained only for compatibility. The recommended alternative is the Microsoft.Extensions.Diagnostics.Testing package.", error: true)]
+    public class FormattedLogValues : IReadOnlyList<KeyValuePair<string, object?>>
+    {
+        private Microsoft.Extensions.Logging.FormattedLogValues _inner;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="FormattedLogValues"/> class.
+        /// </summary>
+        /// <param name="format">The format string.</param>
+        /// <param name="values">The values.</param>
+        public FormattedLogValues(string? format, params object?[]? values)
+        {
+            _inner = new Microsoft.Extensions.Logging.FormattedLogValues(format, values);
+        }
+
+        /// <inheritdoc />
+        public KeyValuePair<string, object?> this[int index] => _inner[index];
+
+        /// <inheritdoc />
+        public int Count => _inner.Count;
+
+        /// <inheritdoc />
+        public IEnumerator<KeyValuePair<string, object?>> GetEnumerator() => _inner.GetEnumerator();
+
+        /// <inheritdoc />
+        IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+
+        /// <inheritdoc />
+        public override string ToString() => _inner.ToString();
+    }
+}
diff --git a/src/libraries/Microsoft.Extensions.Logging.Abstractions/src/LogValuesFormatterObsolete.cs b/src/libraries/Microsoft.Extensions.Logging.Abstractions/src/LogValuesFormatterObsolete.cs
new file mode 100644
index 00000000000000..2cb2c1475513bf
--- /dev/null
+++ b/src/libraries/Microsoft.Extensions.Logging.Abstractions/src/LogValuesFormatterObsolete.cs
@@ -0,0 +1,43 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+
+namespace Microsoft.Extensions.Logging.Internal
+{
+    /// <summary>
+    /// Formatter to convert the named format items like {NamedformatItem} to <see cref="string.Format(IFormatProvider, string, object)"/> format.
+    /// </summary>
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    [Obsolete("This type is retained only for compatibility. The recommended alternative is the Microsoft.Extensions.Diagnostics.Testing package.", error: true)]
+    public class LogValuesFormatter
+    {
+        private readonly Microsoft.Extensions.Logging.LogValuesFormatter _inner;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="LogValuesFormatter"/> class.
+        /// </summary>
+        /// <param name="format">The named format string.</param>
+        public LogValuesFormatter(string format)
+        {
+            _inner = new Microsoft.Extensions.Logging.LogValuesFormatter(format);
+        }
+
+        /// <summary>Gets the original format string.</summary>
+        public string OriginalFormat => _inner.OriginalFormat;
+
+        /// <summary>Gets the list of named format parameter names.</summary>
+        public List<string> ValueNames => _inner.ValueNames;
+
+        /// <summary>Formats the given values using the format string.</summary>
+        public string Format(object?[]? values) => _inner.Format(values);
+
+        /// <summary>Gets the key/value pair for the format item at the specified index.</summary>
+        public KeyValuePair<string, object?> GetValue(object?[] values, int index) => _inner.GetValue(values, index);
+
+        /// <summary>Gets an enumerable of key/value pairs for all format items.</summary>
+        public IEnumerable<KeyValuePair<string, object?>> GetValues(object[] values) => _inner.GetValues(values);
+    }
+}
diff --git a/src/libraries/Microsoft.Extensions.Logging.Abstractions/src/NullScopeObsolete.cs b/src/libraries/Microsoft.Extensions.Logging.Abstractions/src/NullScopeObsolete.cs
new file mode 100644
index 00000000000000..3a40e0d83cab7e
--- /dev/null
+++ b/src/libraries/Microsoft.Extensions.Logging.Abstractions/src/NullScopeObsolete.cs
@@ -0,0 +1,30 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.ComponentModel;
+
+namespace Microsoft.Extensions.Logging.Abstractions.Internal
+{
+    /// <summary>
+    /// An empty scope without any logic.
+    /// </summary>
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    [Obsolete("This type is retained only for compatibility.", error: true)]
+    public class NullScope : IDisposable
+    {
+        /// <summary>
+        /// Returns the shared instance of <see cref="NullScope"/>.
+        /// </summary>
+        public static NullScope Instance { get; } = new NullScope();
+
+        private NullScope()
+        {
+        }
+
+        /// <inheritdoc />
+        public void Dispose()
+        {
+        }
+    }
+}
diff --git a/src/libraries/Microsoft.Extensions.Logging.Abstractions/src/TypeNameHelperObsolete.cs b/src/libraries/Microsoft.Extensions.Logging.Abstractions/src/TypeNameHelperObsolete.cs
new file mode 100644
index 00000000000000..5c6fbe7aada6d5
--- /dev/null
+++ b/src/libraries/Microsoft.Extensions.Logging.Abstractions/src/TypeNameHelperObsolete.cs
@@ -0,0 +1,20 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.ComponentModel;
+
+namespace Microsoft.Extensions.Logging.Abstractions.Internal
+{
+    /// <summary>
+    /// Helper to process type names.
+    /// </summary>
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    [Obsolete("This type is retained only for compatibility.", error: true)]
+    public class TypeNameHelper
+    {
+        /// <summary>Pretty prints a type name.</summary>
+        public static string GetTypeDisplayName(Type type)
+            => Microsoft.Extensions.Internal.TypeNameHelper.GetTypeDisplayName(type);
+    }
+}