The term "rest stroke" comes from the classical guitar world. If a player is playing a "single line" piece with no bass notes or chordal content, that's how they play, using alternate strokes of the index & middle fingers, walking into the next string, thereby creating a damping effect. (Much like us bass players, really!) I use this technique & also left hand damp at the same time.
I also use extra "damped hits" on the right hand for damping and percussive effects as well.
There are some interesting videos of Gary Willis showing his more advanced version where he actually uses unused fingers to further damp strings he's moving away from. Scary!