YouTube's website appears to support picture-in-picture (PiP) again in the latest iOS 14.5 beta for iPhone, although how long it will continue to work for is anybody's guess.
Tests show it works in Safari as well as third-party browsers like Chrome and Firefox by expanding a video to play fullscreen, and then tapping the small picture-in-picture icon in the top-left of the interface.
Then you can minimize the browser and use other apps while continuing to watch the video in a frame that can be moved around the screen or slid out of sight if you just want to listen to the audio.
Apple added PiP support to the iPhone with the release of iOS 14, which allowed users to watch videos on YouTube's website as well as on a host of other websites in the miniaturized format.
Following the release of iOS 14 in September, YouTube moved quickly to nix the ability to watch videos in PiP mode on its website unless the user logged in with a YouTube Premium subscription. In early October, however, YouTube mysteriously restored PiP support for videos on its website.
Then, only days later, support once again vanished.
In the latest iOS 14.5 beta, Picture in Picture mode is working again on YouTube’s website, in not just Safari, but in every browser I have on my iPhone. ¯\_(ツ)_/¯ pic.twitter.com/pP8cRsO3xU — Tim Hardwick (@waxeditorial) February 10, 2021
It's not clear what has caused YouTube website PiP support to be reinstated in the latest iOS 14.5 beta, but it's likely that changes in Apple's system-level code has broken whatever method YouTube implemented on its website to make the feature non-functional.
If that's the case, there's good reason to believe that YouTube will move to disable the support yet again.
YouTube's native app has never supported PiP for any of its users even though iOS 14 has offered the capability for some time. There have been reports that YouTube has been testing this feature, but there have been no announcements.