Updating the API docs has been on the ToDo list for one and a half year. Turns out being on vacation far away from a laser cutter is helping. Not only did I update some doc strings - which are the basis for the Sphinx generated API docs - but I wrote some new documents:
And I added an Introduction to the Edge classes. The rest of the page probably still needs some work as some Edge types are still missing. The Settings classes and their role in creating the HTML and Inkscape user interfaces and in creating the Edge instances probably also deserves a bit more text.
What also helped getting it done - probably not getting it done well - was a good amount of medication. It at least prevented me from doing something more complicated - and may be more rewarding - instead. I hope it does not show too much. So if something looks weird or doesn't make sense please open a ticket on GitHub or leave a comment below.