The Witcher: Total War - Developer Diary 1.5 news - Mod DB
Just an FYI in case we don't get a new signpost, the area circled has several unmarked events that will occur throughout the game after various progress points. I think this is
Crow's Perch at The Witcher 3 Nexus - Mods and community
Crow's Perch and Hattori Fast Travel at The Witcher 3 Nexus - Mods and community