FWIW, I did a half-assed implementation of Ralf's observations yesterday morning (replaced LocalSelectionTransfer with the correct class, disabled ShowInNavigatorAction (which doesn't exist because the navigator no longer exists) and then just disabled a couple of usages of a removed constant (IPageLayout.ID_RES_NAV) which I have no idea what does. Then used 2023-06 throughout the day with the "fixed" plugin and it seems to work fine (apart from of course, you know — "show in navigator" not working from the related view so that would have to be removed or replaced with something else).
- hugi