(Author here.)

> fork the repo (at whatever tag makes sense), then periodically sync with the latest code for that version.

Yeah, this is the workflow that Lappverk is trying to enable.

The problem is that neither of Git's collaboration models works well for this problem. Rebasing breaks collaboration (and history for the patchset itself), and merging quickly loses track of individual patches. Lappverk is an attempt to provide a safer way to collaborate over the rebase workflow.

But you can always create a new branch before rebasing if you want to store the old revision metadata. or do a git format-patches if you don’t want a bunch of branches laying around. So what are the ways to be safer than this?