ref: 8a6a354e22521e7d2d14b8b4c2d1b7a65a0c8d5e 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