While the nature of the object can only be speculated until Yutu-2 gets closer, it is unlikely to be a bunker left behind by an interplanetary species.

It is more likely to be a boulder or a piece of debris, like several others in that region of the moon.

The Yutu-2 rover was launched in 2018 by China as part of the Chang’e-4 lunar lander mission. It entered lunar orbit on December 12, 2019, before scripting history on January 3, 2020, by becoming the first mission to accomplish a soft landing on the lunar surface.