https://github.com/pqrs-org/osx-event-observer-examples Docs on mac input observation: https://docs.google.com/presentation/d/1nEaiPUduh1vjks0rDVRTcJaEULbSWWh1tVdG2HF_XSU/edit#slide=id.p
https://github.com/pqrs-org/osx-hid-inspector osx-hid-inspector is a command line tool for macOS for inspecting human input devices (HID).