I've been looking for a Firefox Add-On like this for a long while.

The Add-On works as intended. If we only consider if the Add-On works as described = 5 Stars.

I would like to make some enhancement suggestions but I haven't found a Github linked to this Add-On. I would have rated 5 Stars if there could be 2 sets of configurable "Rewinds" and "Forwards". Configurable: meaning for example, the user could define how many seconds Rewind #1 goes back, and how many seconds a Rewind #2 would go back. Example: User defines Rewind #1 = 5s, Rewind #2 = 20s. And the same for Forward #1 and #2.