Today's PTR build adds the splash screens for the release of Patch 9.2 and the beginning of Season 3.
Sorry, no actual release date yet though!
Patch 9.2 Release Day Splash Screen Season 3 Begins Splash Screen Patch 9.2 PTR Build 42174 DataminingPatch 9.2 Splash Screens Mythic+ Season 3 Titles — Cryptic Hero PTR Development Notes Class & Spell Tuning ChangesTier Changes — Fury Warrior, Holy Pal, Rogue, Shadow Priest Class Changes — Holy Paladin, Kyrian Druid ModelsStory Spoilers. Read more on wowhead.com