Ploverwing- I think I stumbled into a decent example of that tab symbol a few moments ago. While working by ear (no tab involved) through the melody of Brahms Lullaby, I realized that the 4th and 8th notes (each which is probably a 1/4 note and might even be an 1/8th) needs exactly that sort of muted / half pull-off movement.
I was initially trying to pluck a note one step lower but it sounded far too “elementary/ cartoonish” in comparison to the mute pluck. If that seems clear as mud, I’m referring to the necessary (at least to my own ear) percussive note after “Lou” if you sing the words “La La Lou”.
Of course, there is always the possibility that the melody I improvised wasn’t actually Brahms Lullaby. If so, whatever it was, adding those percussive notes took it up several notches.
Cheers!