[__david__]

Oooo, thank you! Knowing that existed led me to https://developer.apple.com/library/archive/documentation/Co... and https://developer.apple.com/documentation/appkit/nsstandardk...

This leads me to believe that this will work:

    "~t"      = "transposeWords:";               /* M-t */

Edit: Sadly, `transposeWords:` doesn't work, despite showing up in Apple's docs—it just beeps when I try to use it.