**TL; DR: Although well-intentioned, the way this extension works enables Echo Chambers and Censorship to thrive, and may go against the idea of a "Healthy Internet"; but at least it's open source.**

Positives: At least I can find a plus on the Open Source...

Negatives: Having read all the Instructions and Privacy Notice, analyzing it through my personal lens on Censorship and Echo Chambers, and using it for a little while, I can safely say this could be a tool for censorship and echo chambers. (Suggestions will be sent later to Mozilla.)
This is specially worrying given the bottom disclaimer on the RReporter page:

"This is part of a broader movement for a healthy internet."

Slows down YouTube so much it becomes sluggish even on a high-level PC (and even more if it's dated, tested on two systems).
And who the heck opens a video he does not like? Don't see how this can improve my experience.

No idea why you're doing this, complete waste of time.

So, Mozilla fires a lot of developers because of financial problems and this is how it decides to spend some of the remaining resources? Analyzing YouTube's usage statistics? Really?
Mozilla should realize a simple fact: if Firefox dies - Mozilla dies. Developing the FOSS privacy-oriented feature-rich browser should be the main and almost single priority for Mozilla. There are tons of things to improve in Firefox.
Just an example - integrating the Tree Style Tab extension natively into Firefox would be a killer feature.
Also the Mozilla VPN was a good idea. But where is it? Why is it still not available?