I’m looking for a key frequency counter that runs on linux. I want to track actual key usage including all modifier keys, and keybindings as I work with my setup throughout the day. This information will be used to justify minor modifications to my layouts.
There’s a keylogger plugin for Kaleidoscope, you can use that to collect information (via USB serial) about pretty much all key events, including dead keys. With a little help on the host side, you could even make a nice heatmap. (We also have a Heatmap plugin, by the way.)
There’s also Whatpulse, but it’s not open source, and you need to reinterpret its heatmap, because it displays it on a standard keyboard. It doesn’t support custom layouts either.