Feature or script request: 50% guides

Is there now, or could there be, an easy way to create guides at 50% of distances (either two selected points and/or the beginning and ending of a mouse drag)?
I miss FontLab Studio’s contextual-menu ability to create guides at 50%.

What do you want to do with it?

It comes up now and again that I want to find the middle of a stroke, find the middle of a counter, or set up a guide for positioning diacritics, etc.

Sounds like a script. I’ll see what I can do.

https://github.com/mekkablue/Glyphs-Scripts/tree/master/Guidelines

Oh, there’s a new category and “Guideline through selected nodes” went official! That’s the script I use the most.