It's been about 10 years since I touched that code, so apologies if these are all things you know.

I am pretty sure most of the work was just extending the documentation in https://developer.apple.com/library/archive/documentation/La... with looking up application "dictionaries" (iirc, a box of supported commands) and all menu items being accessible by default.

https://developer.apple.com/library/archive/documentation/Ap...