With the new feature of ‘open corners’, it would be very handy if Glyphs could place on the intersection of the paths a third kind of node (An ‘open corner node’, maybe a triangle, coloured yellow). That makes it possible to see the position on which the intersection is positioned.
That is right 
But it is not selectable, and for example, measuring distances & extrema by selecting nodes is not possible without node (leaving out the measuring tool).
What exactly do you want to measure? How often do you need that?
You can switch to the TrueType Instructor tool (I), and fetch the intersection’s position with GSHandle.position(), but it is not fully implemented in the API yet, and in the Instructor, the positions of the intersections are not rounded.
My image is from an ‘e’. I want to measure the size of the opening. The same counts for a sharp ‘a’ and ‘c’, and ‘z’ or ‘Z’ for example.