Could be simpler to think of it as each package having a separate repository with an independent history. Then you cannot have any conflicts from one package on another. This is equivalent to Monticello, right?

Then if you want to combine multiple packages together then you would create a new repo that merges each package that you care about. Once you update packages this repo could either be updated (add more merge commits) or replaced (recreate from scratch with the versions you really want.) This is equivalent to Metacello, right?

The orphan commit trick is then simply a way to multiplex as many "logical" repos (for Monticello packages or Metacello configurations) into the same actual Git repo (as branches with separate roots.)

However -- Can still be that I am misunderstanding the overall goal here.

One thing that I care about, and am a bit surprised that nobody else apparently cares about (?), is being able to snapshot all sources/dependencies in one file/directory/repo/etc that can be loaded from a local file without crawling the internet. Could importing projects into a Git repo that Metacello accesses be a solution? (Or is there already a way today that I am missing?)