Thanks for the clarification! This is what I suspected, too. What matters to me is that it works with custom extension lists. I am not sure I understood what was special about the original "2020 Fennec".

There's also a note from someone on Reddit [1]:

> Fennec is also F-Droid's firefox version. It differs from official ones by having proprietary bits and all telemetry removed as well as unlocked about:config at the moment.

[1]: https://www.reddit.com/r/firefox/comments/nff8sv/comment/gyl...