Can someone makes me a few examples?
This is currently no official feature of Plex.
I have to correct myself.
This is a new feature, but support for it is currently only in the Plex clients on Roku and Android. That’s why it is not officially announced yet.
The other clients (including Plex Web) don’t support them yet.
I’ve heard that “White Collar” has extras available.
I can confirm that some extra for TV shows appared only on my android app, but some one don’t work, here are few examples:
Agents of Shield - trailer available but plex won’t play it
2 broke girls - tailer available and working
Aquarius - extra available and working
falling skies - trailer available and working
the simpsons - extra and trailer available
I didn’t do nothing on the server, they just pop up.
Great news for plex pass users 
