In 19.04, in X sessions, fullscreen displays such as Youtube videos were unredirected from Mutter compositing. That was obvious while using the intel modesetting driver, from the tearing.
However, now that I switched to 19.10, I notice no more tearing on fs Youtube videos. In an older window manager such as Metacity however, tearing is still atrocious so I know the change isn't coming from the driver.
So is it just me or did Mutter stop systematically unredirecting full screen program displays ? And then, did they go back to unconditional compositing or are special criteria used to avoid compositing games' displays ?