Not my house, so I'm not 100% sure if this boulder was placed or part of the house.
Even if it were a decoration, I'm pretty sure I'm not supposed to be able to go inside it.
This is just inside the door marked "Twin Arches Courtyard"
I have this house, though I do not go there much anymore.
I can’t recognize what I’m looking at, but I don’t remember any boulders inside the courtyard. This seems very odd. Is that arched door at the bottom right of the image the one that leads back out into Bangkorai?
I finally managed to get in touch with the owner. Turns out they deliberately put a big rock right there so that you would exit that door right into the inside of that rock <.<