The Microsoft.WindowsDesktop.App.versions.txt files in the nupkgs say core-setup <commit hash>. This is defined in the shared framework tooling SDK, I missed it when implementing it:
https://github.com/dotnet/arcade/blob/663f5c6784b20b4c95ce92f0e4777af35b5eb771/src/Microsoft.DotNet.Build.Tasks.SharedFramework.Sdk/targets/framework.dependency.targets#L112
The obvious fix is to change that side to take an optional property to pick the repo name, and a change in dotnet/windowsdekstop to set it to windowsdesktop.
This file has no immediate infrastructure use, so this doesn't seem critical. However, people still may read it and would be misled.