so I found that the switch to resetting full world folders isn't as backwards-compatible as expected... starting to reset level.dat file can cause issues if you have mismatching gamerules from the previous system
so I have added a new option:
Code (Text):
#whether it should only reset "region" world folder contents and not other things like level.dat (It's cheaper to reset only region folder, but it doesn't reset world metadata, only the chunks, which may be not what you wish)
ResetOnlyRegionFolder: false
additionally I have added a new command
/fwr optimize-template <world>
it will show you the files that may be unneeded in the template and should be deleted, it's only a recommending command, it does not delete anything automatically.