Right rear tire cable disconnected

Help I just noticed I have a cable disconnected from my rear right tire. I have no idea what this is. my brakes work fine. Does anyon know what this cable is. I see it is still attached to the left side near rear tire?

:p well I did have it checked out and :silly: me it was the plastic cover to the cable.

Just off the cuff, sounds like the emergency/parking brake cable. Should check it out or have it checked out for your own safety as well as those around you.