Rosetta 2 kicks in, performs a JIT/AOT translation of the x86 instructions to ARM instructions, executes those, and caches the resulting ARM binary for later use.
Please stop being so hostile to other users. It really doesn't add anything. You have made some factually questionable comments yourself, and I say this as someone who has worked on JIT aarch64 translation very similar to Rosetta 2.
What is it doing when it runs x86_64 binaries then?