It is available to provide pass through power to another device or camera. It is of limited usefulness if the camera is allowed to rotate with a cord attached to that port. I use it to power my small travel router which I double-stick taped to the top of the Pan and attach to the USB-A port with a 6" USB cable.
There was at one time a plan to allow a USB stick inserted into the port to serve as onboard storage, similar to the microSD card. This has not been implemented.
Thank you very much
You can also use the port for the Bridge adapter for the V1 Wyze Sense. (Although many people have had issues with attach the Bridge onto the Pan Cam.)
Yeah, I would definitely recommend against using it for the Wyze Sense bridge. It seems to overload the weak processor for some reason. I used to use one of my bridges in my pan cam, but quickly decided that was a bad idea that would wear it out fast since both became unstable with it in.