Hi, an upbge user was trying to have this addon working, and it doesn't seem to work after 2.92 alpha.
We did a bisect to know since when it was broken exactly and it is since this Blender commit:
https://developer.blender.org/rB246efd7286f6187e4dd4b3edcc79cccb1746bb1d
Idk if it can be fixed in the addon code or if it requires something in blender code, but we just wanted to inform you about what we found.
Regards.