The radio is an 'update list' type. Images of connections and front panel attached.
The yellow plug is the CAN bus connector. Other items on the CAN bus that are related to the radio, are the display and the remote,
so removing this connector would deprive you of visual feedback from the display, and the possibility of changing volume, track and source from the steering column.
The two black, large connectors are for standard car stereo things, like speakers, power, ignition, panel illumination, etc.
The two empty connectors next to the CAN bus are for analog AUX in, and for CD changer (S/PDIF).
But since CD changers are sooo 90's, that's where the iPod adapter goes instead.