I imagine they will receive a cease and desist?

Did they reverse engineer something?

This is a clean room open source implementation. Not property blobs are used.

Additionally Apple intentionally designed the M1 architecture to support additional OSes. They have even made changes to their code that have fixed issues the Asahi project was having. So while there's no official support this project is certainly known to Apple and has raised no concerns so far.

Could you explain what Apple changed in their code to help Asahi?

Didn't you just say no proprietary code is used?

I'm confused.

AFAIK to reverse engineer Asahi runs a virtual machine between macOS and hardware. If Apple made changes in the code then perhaps these helped make the instruction logs more obvious as to what the GPU was doing.