Some other links:
- PR which added the testing note: Note that CI tests Windows 10 by ChrisDenton · Pull Request #95861 · rust-lang/rust · GitHub
- You can argue this is effectively "soft" demoting x86_64-pc-windows-msvc on pre-Windows 10 to Tier 2.
- .NET support for Windows 7 and 8.1 will end in January 2023 · Issue #7556 · dotnet/core · GitHub
- Chrome support for Windows 7 now until January 15, 2023 | Google Cloud Blog
Consensus does appear to be that Windows 7/8 are effectively tier 2, but how to best communicate this is unclear.