Where are the runner mappings defined?

[TWiStErRob]

I found the definitions of the images:
https://github.com/actions/runner-images/blob/main/images/linux/ubuntu2004.json

I'm looking for where ubuntu-20.04 (which is used in run-as:) is mapped to this file. I understand there might be multiple steps involved, for example this image is built, versiones and pushed to some repo. I'm most curious about the top level definition.

Maybe a simpler question could be, where is ubuntu-latest defined to point at ubuntu-22.04?

[mikhailkoliada]

Hello! It is out of scope of the repo as it is defined by an inner github's backend

[TWiStErRob]

So it is not listed in any other public repo you know either?