Probably not the best place to discuss, but I just realized something while applying labels: we probably should have been backporting some of these, otherwise other changes that get backported to these modules will conflict. WDYT? (It's good that Petr is tagged on this, I'd like to hear his opinion too.)

I don't think we should be backporting all of them preemptively. But if you get conflicts, it's probably best to backport the UB PR first.

I haven't backported the changes which caused conflicts on a recent PR but I resolved them manually. I'm afraid that the backports of UB PRs would actually be harder because #128447 was not backported.