what's the easiest way to get a set of resources built in a docker_environment out of the docker sandbox and back into the actual project directory?

Do you want to commit the files generated by a command run in a

docker_environment

? Or do you want access to them transiently (e.g. for uploading to a release or a cloud environment)?

the former. I have files that I need to compile on an x86 machine that are done via pip install. I can gather the files up, but once they are done in the docker environment there isn't a simple copy target.

For committing, https://github.com/pantsbuild/pants/discussions/18235#discussioncomment-6655594 is what we do (and that discussion captures what a potential future state is)