How do you add a custom label to a vertex? I would simply like to put an arbitrary, non-mesh/curve text label next to any vertex that sticks there in a manner similar to the 3D cursor itself. I have not found a way to do this so far, but I would imagine Blender would not be so careless is to exclude the basic capacity for displaying text that even notepad and MS paint are capable of.
After installation ( Header > Edit > Preferences > Add-Ons tab ) the shipped '3D View: MeasureIt' add-on can be used to label vertices, just using the 'Label' option:



They can be rendered, too, but I don't think you can suppress the line between the text and the vertex..