ref: 2c9f4c21ad0b5e66f06a3613f6e21d5fe9f0da6a dir: /sys/lib/kbmap/mouse-fn/
# Use F1, F2, F3, F4, F5 as mouse buttons (useful on laptops) 0 59 M1 0 60 M2 0 61 M3 0 62 M4 0 63 M5