Better documentation around building with eas/ steps in the custom yml build configs

Where do I post `eas-build` issues?

### Summary

I'm having a really hard time taking (read: finding) outputs from `eas/` prefixxed steps and using them in other steps.
build failed var doesn't exist..
build failed var doesn't exist..
build failed var doesn't exist..

It feels very much like a black box.

the documentation here:
https://docs.expo.dev/custom-builds/schema/
and here:
https://docs.expo.dev/eas/workflows/syntax/
is insufficient. Each eas/ step should include a list of outputs that are available.

Even just dumping the outputs (of steps, run_gradle, etc...) to the log is something that I can't do (have tried)

### Managed or bare?

managed

### Environment

not related

### Error output

_No response_

### Reproducible demo or steps to reproduce from a blank project

any custom yml config