Unfortunately it’s not currently on F-droid but it seems like that is a planned goal.
Edit: I came across this project while looking for an alternative, because Fennec F-Droid did not sync my history with my desktop browser when I installed it. I did, however, reinstall it and this time it worked, so I am now using Fennec.
It’s something close: https://discourse.mozilla.org/t/about-config-missing/66537/6
It’s a strange justification, just like saying they were no longer supporting the “compact” layout because on desktop people were unaware of the feature.