Collision or aircraft proximity warning?

I am relatively new to IF and was recently doing an English Channel hop to Jersey (EGJJ) for some crosswind landing practice in the SR22.

Whilst en route I was harrassed by an idiot in an F16 who mistook me for a target drone. I’m aware this is not an unusual occurrence on the casual server and, to be honest, it didn’t really annoy me all that much. I knew he would soon get bored and disappear, but before doing so, he circled me one last time, came upon me from astern and his aircraft went red momentarily on my cockpit map. I wasn’t looking directly at the map when this happened, but I caught it in my peripheral vision.

My question is this: did the change of colour indicate a collision had actually occurred (as I assumed) or was it a proximity warning, if such a feature exists in IF?