Initially limited to only Premium users, YouTube's picture-in-picture (PiP) mode is now rolling out to non-Premium subscribers outside the US.
YouTube's PiP mode is currently rolling to non-Premium users in Italy, and is likely to be introduced to other countries gradually.
"The option to turn on PiP mode can be found in Settings > General menu in YouTube's Android app, but it only works on devices running Android 8.0 Oreo or later versions," the GSMArena recently reported.
However, according to Google's support page, non-paying users in the US are being able to benefit from PiP playback with advertisements.
Users who don't have a YouTube Premium subscription can play a video (non-music one) then exit the app and see if it stops or goes into PiP mode.
They can also double check for the setting in the app.