Essentially, our current code would not properly remove (dereference) its python objects matching various RNA data created during execution. Some cases are fairly trivial to understand (like the lack of handling of unregstering for our 'startup' operators and UI), other were more subtle (like unregistered PropertyGroups who would remove/free their RNA struct definition, without releasing first the potential matching python object). Co-authored-by: Campbell Barton <campbell@blender.org> Pull Request: https://projects.blender.org/blender/blender/pulls/128899