It creates a ‘marker’ so you can jump back there. Doubleclicking the marker deletes it.
Confused me for a while when my hand did it involuntarily and I didn’t know what it was, now I am in love.
Couldn’t find any documentation of it so here it is, the hype train. Here’s the commit, apparently I am behind the times by a whole year and a bit.
It feels like KDE is just a goldmine laced with hidden gems. I swear I stumble across one of these a couple times a week. Hope you all like this one.