While this one seems like an official Google project, some other projects are not, even if it is on github.com/google

A random example E.g https://github.com/google/filament#disclaimer

This is not an officially supported Google product.

Fair enough, I missed that specific line. The point still stands that I wouldn't expect this to have GDM leadership backing. (If you're planning to use this at all, that matters for how much faith you should have in the product.)