To install, first copy the cyborg16 file to the xkb/symbols dir:
sudo cp cyborg16 /usr/share/X11/xkb/symbols/
If you're running X11 that's already enough to test; e.g. to set the basic variant (under restart or otherwise adjusted):
setxkbmap cyborg16 basic
But if you're running Wayland that won't do anything.
Now, open evdev-extension.xml and copy the contents, then open xkb/rules/evdev.xml for editing:
VISUAL=kwrite sudoedit /usr/share/X11/xkb/rules/evdev.xml
Paste the contents you copied here, under the xpath /xkbConfigRegistry/layoutList (i.e. just after <layoutList>).
Now, restart the display manager (e.g. systemctl restart gdm.service), and the new layouts should show up in your system settings.
Alternative (X11 only): edit the system's default X11 settings under /etc/default/keymap or /etc/X11/xorg.conf.d/00-keyboard.conf or similar.