Hi,

Investigating backspace and delete here. These are the best documents
I've found.
(1) https://en.wikipedia.org/wiki/Scancode
(2) https://aeb.win.tue.nl/linux/kbd/scancodes.html
(3) http://www.beyondlogic.org/keyboard/keybrd.htm
(4) https://wiki.archlinux.org/title/Keyboard_input#Identifying_scancodes

Referring to (4), "showkey --scancodes" and "showkey --keycodes" give
these. View in fixed pitch font.

keycap     scancode  scancode  keycode  keycode
           down      up        down     up
===============================================
Backspace  0E        8E        14       14
Delete     E0 53     D3        111      111

"evtest /dev/input/event1" confirms those numbers and adds MSC_SCAN.

keycap     scancode  scancode  keycode  keycode  MSC_SCAN
           down      up        down     up       value
=========================================================
Backspace  0E        8E        14       14       7002A
Delete     E0 53     D3        111      111      7004C

Questions

(5) Ideas about MSC_SCAN? How is the acronym derived? The number is
produced by key down. Nothing for key up? Five digits is enough for
Unicode?

(6) How does Xorg represent keys or key codes? Uses the above?
Distinct Xorg key codes?

(7) systemd is mentioned in
debian:/usr/lib/udev/hwdb.d/60-keyboard.hwdb . runit has something
parallel?

Thx,                   ... P.

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