It means the AI Vision camera, the marker stickers that come with it, and code you write yourself. It does not mean a Rover that works out its own way around a room: as it comes out of the box the Rover is driven by you over radio, and there is no self-navigation or obstacle-avoidance mode in the firmware it ships with.
What the vision side actually does. The camera sends a live feed of what the Rover sees to the Mission Control module you build, so you can drive from the Rover's point of view. The ArUco marker stickers supplied with the camera are what it recognises: place a marker where the Rover can see it, and you can have the Rover run an action when it spots that particular marker. If you are not sure which camera modules came with your order, send your order number to us here, or by email to [email protected] and we will check.
What you program. Which marker means what, what the Rover does when it sees one, and whatever you want to build on top of that. The Rover's firmware is open source and written in C++ with Espressif's ESP-IDF environment, so that is the route for changing how it behaves; there is more on the coding options in What programming languages can I use with CircuitMess kits?. The Rover can also be extended with additional sensor modules, so if you want it to react to something the kit does not sense, that is a module you add and code you write.
Worth knowing before you start. Running your own code from CircuitBlocks writes a MicroPython image over the firmware the Rover shipped with, so the radio remote control and the camera feed stop working until you put that firmware back with Restore firmware at code.circuitmess.com. Nothing is damaged by the swap and it takes a couple of minutes to reverse.