The reason that we can still have new Clements updates for AviSys is that many years before closing AviSys, Jerry Blinn provided an "AviSys' author was run over by a truck" facility, called EditMaster. Unfortunately Editmaster does not perform everything that goes into an update, and I still needed to do extensive research and development to come up with a set of tools that not only update the taxonomy, but also the state checklists, band codes, subspecies data, and jump tables, as well as synchronization with the ABA checklist. In fact, I no longer even use EditMaster but have written my own replacement for it. So, in the "author run over by a truck" spirit, I am making public the tools that I use to perform an update. They will be most meaningful to someone who understands the Python programming language, but they should be usable by anyone.
Tools on github