What is this cable for?
Yellow and white generally mean video (yellow) and mono audio or left channel audio (white).  It is fairly typical for a usb like port to be used as a video connector when the proper cable is inserted.  It sometimes even uses the same exact port.  

Note that it requires special hardware in the camera.  You can't simply plug it into any USB port and expect it to work.  RCA's carry an analog signal while USB is digital.  There is however a system called MHL that is often present in smartphones that allows output of an HDMI signal over the USB port, though external power is often required.