Comment by gorgoiler

Exactly! A stack of PRs is really the same beast as a branch of commits.

The traditional tools (mailing-lists, git branches, Phabricator) represented each change as a difference between an old version of the code and the proposed new version. I believe Phabricator literally stored the diff. They were called “diffs” and you could make a new one by copying and pasting into a <textarea> before pressing save*.

The new fangled stuff (GitHub and its clones) recorded your change as being between branches A and B, showed you the difference on the fly, and let you modify branch B. After fifteen years of this we are now seeing the option for branch A to be something other than main, or at least for this to be a well supported workflow.

In traditional git land, having your change as a first class object — an email or printout or ph/D1234 with the patch included — was the default workflow!

*Or some other verb meaning save.