There was an addon I found some years ago and it allowed you to select some edges from a model, add them in a list and then draw them with BGL. The result would be to draw various so called “selections” of various models at once.
Unfortunately I don’t remember how this addon is called and where to find it. If you know anything about it let me know.
Not exactly this, it was something else. There is a high chance I might not find that one and it’s a real pain to search it. I think I might need to create it myself. I found here some good foundations for getting started.
But thanks Alberto for the suggestion because Edge Fillet features some relative code and it worths studying.