This is one of the scripting languages used in the Source Engine. I believe the first game that supported it was Left 4 Dead 2, it was certainly the first time

This is one of the scripting languages used in the Source Engine. I believe the first game that supported it was Left 4 Dead 2, it was certainly the first time I heard of it. https://developer.valvesoftware.com/wiki/VScript https://developer.valvesoftware.com/wiki/VScript