Excatly. It's bare, and connected to the earth terminal of the device, and in applicable cases to a metal box. What else would it be but an earth/ground?The absence of insulation surely serves as very clear identification.
Not sure what BS7671 says about those now, but the one which used to be required to be insulated throughout its length was the conductor running from the earth electrode to the "E" terminal of the old voltage-operated ELCB. Wiring on the "F" side of the coil didn't matter.... talking of which, is there actually a requirement for things such as bonding conductors and earthing conductors to be insulated? Without looking carefully, I'm not at all sure that there is. They certainly didn't used to be in many cases.