I think they did a great job it titles like Bloodborne, Demon's Souls, Death Stranding or Stellar Blade.
So it's the new Japan Studio
Team Asobi is that it was the internal development part of Japan Studio.
XDEV Japan is what it was the second party publishing/support part (XDEV) of Japan Studio.
Both continue working in the same Sony HQ building and doing the same than before, but now as separate entities.
Death Stranding is no longer a first party game, ownership of IP changed hands (and 505 publishes everything except PS release). It's still a bit of a weird one, was funded by Sony and uses a Sony engine.
Death Stranding and DS2 continue and will continue being PS first party games because continue being published on PS by its platform holder. The IP ownership isn't related to being 1st party or not, first party means that the publisher is the platform holder and 3rd party means that the publisher isn't the platform holder.
Having a partner to port it somewhere doesn't make it 3rd party on PS. It's 3rd party on PC because it isn't published there by the PC/Steam platform holder, same as the other Sony games released on PC.
What does XDEV actually do? I honestly don't think anyone here has any clue. Money? Game design tips? Tech optimization over completely different proprietary 3rd party engines? That last one seems especially unlikely.
XDEV = eXternal DEVelopment
They basically manage external development in multiple areas. Basically, they are the Sony team in charge of managing and overviewing the internal and external support teams that the first (which include second) party games use.
This means that for an internally developed game as could be Ghost of Tsushima, they manage different internal support teams like PlayStation Studios Creative Arts (which include people like PS Studios Visual Arts, but also for coders, audio, etc) or external teams (many external outsourcing companies who game specific job for hire for many companies).
And for second party games (2nd party means a game published by Sony whose lead gamedev studio isn't owned by Sony), XDEV is the Sony team who is in charge of them: funding, publishing, providing them any internal or external support they may need, QA, localization, marketing etc.
XDEV is a global team has basically 3 branches/teams:
- The original one in Europe that was a spinoff team of SCEE Liverpool, where they started. They basically are in charge of the games developed in EU.
- The North American one, that was a spionff of Sony Santa Monica, where they started. They are in charge of the American games.
- The Asian one, that was a spinoff of Japan Studio, even if they started back in 1993 before Sony had any internal development team in Japan (had another name, later the internal development team was created, then they merged and then they changed their name a couple times until they separated again). They were in charge of the Japanese games, but now are in charge of games developed in the whole Asia.