Not all of our desiderata for T248186: Prepare Parsoid for MediaWiki 1.35 LTS got done, and we've found some other things that should get done before the next release.
This is a parent task for everything Parsoid-related targeted for 1.36 1.37 1.38. (Often this is because we want to ensure things get deprecated before release so we can then remove them in a future release and clear them as blockers for integrating Parsoid in core.)
We are realistically not going to do all this work before RC0. I am going to remove this as a blocker for MW 1.36 release. We should retarget the tasks for 1.37 and be more realistic and about what we intend to really work on for that release.
The large amount of back-porting isn't going to make it to 1.38, right? We'll just let this ride in 1.39 as the LTS?
Yes. We've manually added 1.38-blocker tags to the few things we do intend to get into 1.38 -- I think that's limited to isabelle's work on Translate improvements at this point (some combination of Translate, VE, and Parsoid patches). Everything else will be 1.39 (and oh boy I probably need to comb through this list and thin it down at some point).