Userscript changes behavior in rythm with Beta release cycle - Why?

So I have this userscript that changes its behavior about every two weeks. Once in the middle of the release cycle and once when a new major version of Firefox Beta is released.

What’s up with that?

What happens two weeks into the Beta development cycle that could explain this? Are there two different internal builds that the Beta versions are built from?

This forum isn’t very active. I suggest you contact the creator of the userscript, or join the Matrix and ask there.