Comment # 18 on bug 1209594 from Stefan Dirsch

@Luca Please test. I suggest to test it the following way

localectl set-keymap de
# check /etc/vconsole.conf and /usr/etc/X11/xorg.conf.d/00-keyboard.conf

localectl set-x11-keymap us pc104 '' compose:lwin
# check /etc/vconsole.conf and /usr/etc/X11/xorg.conf.d/00-keyboard.conf

sudo sh ./keytable
# check /etc/vconsole.conf and /usr/etc/X11/xorg.conf.d/00-keyboard.conf

Do not edit /etc/vconsole.conf manually for testing! For changing things run
localectl set-keymap/set-x11-keymap with different keyboard layouts!