> other than FF, you can also trigger PiP on a YouTube video by double-right-clicking on the video element OR long pressing on the speaker icon on the tab/address bar.

Neither of these worked for me. Chrome 83 on Win 10.

YouTube app on Android supported this some time ago. If you were playing a video and then wanted to go to some other app, a small floating window appeared with that video playing.

It was then locked away behind YouTube Premium, and now YouTube (non-premium) occasionally bugs you to pay for the premium when you try switching to another app so that you can continue playback.

> YouTube video by double-right-clicking on the video element OR long pressing on the speaker icon on the tab/address bar.

I've been using pipifier for this - especially for Netflix, didn't know about this until now - thanks

PiP currently works in Safari on iPad, and will also work in Safari on iPhone starting with iOS 14.

Not sure if it's possible to get a browser-based YouTube video to go PiP on iOS Safari.

PiP works on Firefox (and likely Chrome, haven't tested) for Android. iOS just announced PiP support, but formerly on iPad had PIP. A quick google shows that PiP does work for Safari on iPad.