@Tim Edwards I have a feature request for magic: I would like to have a logging/debugging option for the extract command in magic, which creates an output directory with a .mag file for each device that was found during extraction (which then contains just the necessary geometry for that particular device), and a top level .mag file (or preferably a hierarchy of .mag files if there are any hints that can be used to deepen the hierarchy) which links the devices together. Any metal patches which have a port should get their own low-level "device" as interface. How much effort do you think this would be?

What you're asking for is sort of a "reverse pcell" where you analyze a layout and generate pcells from the layout. I'm sure it's doable. I'm also sure it's a lot of work.