Aventon displays may have a USB port on either the side or the bottom of the display (depending on model).
While this port is initially used for programming, it can also provide assistance in maintaining charge on a cell phone or lights mounted to the handlebar.
While there is output on the display to provide charge to other devices, keep in mind that this is not a dedicated charger and will likely help "maintain" a device's charge but will not provide sufficient power output to fully charge your phone or light.
Below are some examples of what the USB port will look like:
BC 280 Display (USB-A)
BC 147 Display (USB-C)