Numerous Movies, Video Games, and TV shows featuring fighter pilots depict the pilots calling out "Fox Two" on the radio as they fire a missile.
The transmission (as depicted, I'm not sure about IRL) frequently does not include the aircraft identifier (tailnumber or callsign). (but sometimes an aircraft ID is included)
What does this signify? Why is it important? And why is the term "Fox Two" rather than any other variation of "Missile Fired"/"Missile Away"?
How are other pilots meant to respond when they hear "Fox Two" on the radio?