It's used to express the final location or outcome of something.
Here's an example:
* "Le ballon se retrouve où ?" - "Where does the ball end up?"
Here are some other possible translations depending on the context:
* "Where does it end up?"
* "Where does it go?"
* "Where does it land?"
* "What's the final destination?"
Note: It's often used in the passive voice and emphasizes the location or outcome.