As per Mozilla’s Are we Fenix Yet site, Nightly and Beta versions of Firefox for Android have already been migrated to Fenix, soon the current stable version of Fennec will also be replaced by current Firefox version in development. Firefox for Android in Nightly has got Picture-in-Picture mode support, you can now start watching videos in PiP mode on devices running Android 8 or higher.
Recently Mozilla has added five more recommended addons to Fenix after UBlock Origin, these five extensions –NoScript Security Suite, HTTPSEveryWhere, Dark Reader, Search by Image and Privacy Badger.–can be installed in Firefox Nightly version by visiting add-ons in Settings.
After desktop Firefox, Fenix has now got the Picture-in-Picture feature and is enabled by default in Nightly, to see a video in PiP mode in Firefox on Android
1. Download, install and Launch Firefox Nightly on Android
2. Visit YouTube, play any video
3. Go to full screen
4. Click on the Home screen button to see the video playing in Picture in Picture mode.
The hidden preferences present in about:config indicate similar to that to that on desktop, Fenix may well offer a blue PiP button for Videos.
On news related PiP on desktop Firefox, Mozilla has got a positive response for the feature, the browser offers a dedicated shortcut a mute button and in the upcoming version, Firefox allows PiP window to go to full screen when you double click on it.