Oh hey, I just started up kicad-nightly and it said “Welcome to KiCad 6.0!”
I’ve found eeschema’s revamped copy/cut/paste system includes this “Paste Special…” dialog
which not only allows you to cut something from one page and stick it in another without losing the annotations, but (and I think this was not the case earlier in 5.99, at least not at one point, I think) it also keep track of their internal identifiers so when you update the PCB, it doesn’t delete all the pasted components and re-add them, forcing you to place them all again.
Man. Had I known that yesterday I would’ve used the nightly to reorganize pages in my project — I doubt I’ll be wanting to share it before KiCad 6 stable is released anyway!