mine Keyboard Layout on NixOS unstable

mine is an optimized german keyboard layout.

Manual per user install

mkdir -p ~/.config/xkb/symbols
curl https://dl.neo-layout.org/custom_mine_2.39 > ~/.config/xkb/symbols/custom

Add keyboard layout:

GNOME Settings > Keyboard > Input Sources > Add Input Source > Other > A user-defined custom Layout > Add

Choose keyboard layout with the drop-down menu in the top right of the GNOME Shell status bar.

Find directory paths from which keymaps are loaded

If the keyboard layout cannot be found, press the litte eye icon or „View Keyboard Layout“ next to the „A user-defined custom Layout“ entry in GNOME Settings and find the error message in the systemd journal.

bash$ journalctl -et org.gnome.Settings
Apr 08 20:08:07 helium org.gnome.Settings[25083]: xkbcommon: ERROR: [XKB-338] Couldn't find file "symbols/custom" in include paths
Apr 08 20:08:07 helium org.gnome.Settings[25083]: xkbcommon: ERROR: [XKB-338] 1 include paths searched:
Apr 08 20:08:07 helium org.gnome.Settings[25083]: xkbcommon: ERROR: [XKB-338]         /nix/store/3kj098kkfh4mw4d70yjqg1flxzj3xw21-xkeyboard-config-2.46/etc/X11/xkb
Apr 08 20:08:07 helium org.gnome.Settings[25083]: xkbcommon: ERROR: [XKB-338] 4 include paths could not be added:
Apr 08 20:08:07 helium org.gnome.Settings[25083]: xkbcommon: ERROR: [XKB-338]         /home/clerie/.config/xkb
Apr 08 20:08:07 helium org.gnome.Settings[25083]: xkbcommon: ERROR: [XKB-338]         /home/clerie/.config/xkb
Apr 08 20:08:07 helium org.gnome.Settings[25083]: xkbcommon: ERROR: [XKB-338]         /home/clerie/.xkb
Apr 08 20:08:07 helium org.gnome.Settings[25083]: xkbcommon: ERROR: [XKB-338]         /etc/xkb
Apr 08 20:08:07 helium org.gnome.Settings[25083]: xkbcommon: ERROR: [XKB-661] Couldn't process include statement for 'custom'
Apr 08 20:08:07 helium org.gnome.Settings[25083]: xkbcommon: ERROR: [XKB-769] Abandoning symbols file "(unnamed map)"
Apr 08 20:08:07 helium org.gnome.Settings[25083]: xkbcommon: ERROR: Failed to compile xkb_symbols
Apr 08 20:08:07 helium org.gnome.Settings[25083]: xkbcommon: ERROR: [XKB-822] Failed to compile keymap