@zooba I've accepted your suggested changes, but your other comments will require more thought and editing. If you're happy to push the current version of the PR as an interim update until, please go ahead and merge.

OK, I actually addressed the more substantive comments as well. It's a holiday weekend over here, so please merge if you're happy with the updates.

Antoine raised a valid point regarding duplication between the Abstract and the Proposal, so I cut the detailed list of bullet points out of the Abstract.

Added some images based on @ambv's example timeline and support matrix impact in PEP 602.

I also moved the example timeline up the top to reduce the initial "wall of text" impression.

Good job on the pictures, they are helpful. One question: shouldn't 3.10 start in June rather than May? E.g. branch cut happens at RC?

@ambv Thanks for providing the base images for me to start from! (I'm completely hopeless when I'm looking at a blank screen in an image editor).

Under the current text, there's a 4 month preparation window on master between branching the previous RC, and publishing the initial ABI for the next release series. I'll see what I can do to make it clear that that's intentional. The "2 month RC preparation" window actually means skipping two pre-freeze releases for the next series (one at the start, and one at the end), but it isn't obvious that that results in having 4 months to prepare the first alpha for the next series.

I went ahead and merged the update, as the revisions here were substantial enough that reading the previously published version wouldn't give a good understanding of the current state of the proposal.