Felix doesn't appear to have support for extensions. That would be very unfortunate if Mozilla has chosen this route. Hopefully they plan to include support for them.
This is the main reason I use Firefox for Android. Without a good ad-blocker, browsing while commuting quickly blows through my data caps (I am in Canada).
Add-ons are the primary reason I use FF on mobile... browsing the web without an ad/tracker-blocker is pretty horrendous.
Extensions like Ghostery and Ublock Origin are maybe the only reason to use FF on Android, as Brave does adblocking as well and renders pages more smoothly as it's a Chromium fork.
Didn't they also release Firefox Focus recently, also with no extension support?