Squawk 7x00 was detected message

I saw this for the first time this morning but I could not identify which aircraft it was coming from. Could someone shed some light on this for me? I’m running 3.03.

Thanks,

Chris

https://en.wikipedia.org/wiki/Transponder_(aeronautics)#Code_assignments

I am familiar with squawk codes, I wanted to know what I should be seeing in my map. ie… is the aircraft color going to change, blink…
shrug

Yeah, they get a different color.

Explanation of aircraft colors on map please.