Okay, so...
1. Absolutely nothing today.
2. Pre-patch content preview blog early next week.
3. Pre-patch annoucement along with a survival guide video or some in-game trailer later next week.
4. Pre-patch releases on October 6th.
BONUS. There won't be any Jailer CGI trailer for the pre-patch. If there's one, it's either going to be for Shadowlands launch or some time after.