Reworked and updated it for Bender 4.0+
https://github.com/EvilReFlex/ERF_LevelBuddyBlender
The repository's issue page does not exist for whatever reason, so I'll provide this here.
Thankfully I got it to load in especially BFA 4.4.3 (Blender 4.5a), though everything else but Build Map works. Maybe I'm doing something wrong or I just forgot how to use this, but I remember this add-on working whenever you add sectors and clicking Build Map for any change you do.