Your username is vaguely familiar. You're a CUE enthusiast, right? I think I've read (and enjoyed and benefited from) some documentation you've written!

Yeah, I think it makes sense to also let people point to arbitrary OCI registries. I'd bet support for that is coming, especially since the execution environment is Dockerized anyway.

> Pushing nix as the DX for GHA equivalent

I think something like Nix actually makes more sense than YAML for this kind of thing. You want a DSL that is purpose-built so that configurations are declarative, simple configurations are simple to write, and configurations are composable. YAML is too much of a straightjacket. Some kind of built-in support for deep merges is a must, imo.

How powerful/expressive the language should be is debatable, I think. I'm interested in Turing-complete DSLs like Nix and Nickel, but CUE could be a good fit here, too.

Anyway I'm sure they'll add first-class support for using some OCI artifact to define a CI environment. Looks like their CI implementation only recently entered the first alpha.