It's THIS and nothing else.
It just bears resemblance to many different places in the game as the same elements / building blocks are used to create it.
And the Xunlai Market area will very likely become the Embark Beach.
The area is huge. The Training Arena is just a very small part a little south of the middle of it.
I've never seen any other parts of the area used for anything else.
But it's definitely the area that has the Training Arena on it. I just checked in-game.