Prototype

Recently while browsing the Alpine git repo I noticed they have a function called snapshot, see: https://git.alpinelinux.org/aports/tree/testing/dart/APKBUILD#n45 I am not 100% sure about how that works but a wild guess is that the developers can run that function to fetch the sources and maybe later upload them to the Alpine repo or some sort of (cloud?) storage.

In Portage there exists a pkg_config function used to run miscellaneous configuration for packages. The only major difference between src_snapshot and that would of course be that users would never run snapshot.

Sandbox

Probably only the network sandbox would have to be lifted out… to fetch the sources of course.

But also a few (at least one?) special directories and variables would be useful.