It is Linden Scripting Language (LSL) for the Second Life virtual world. You can see a number of programs I’ve written in this language among my GitHub repositories—look for the ones with a language tag of “LSL”. A particularly good example for the vector and rotation capabilities is the Orientation Cube, which is demonstrated in the following video.
This is a model I built to help developers learn how rotations, translations, and co-ordinate transformations work in LSL.