Ubuntu – Why did 13.10 break the custom keyboard layout

The Xkb directory is located at /usr/share/X11/xkb
Besides, it's not XFCE that uses the directory, it's Xkb, a part of Xorg.
To create a new layout just create a file in symbols/ (eg asdf). After that you can switch to the newly created layout with setxkbmap asdf

Next step would be to register the layout, see the files rules/base.xml and rules/evdev.xml.
After registering you can switch to it other than by calling setxkbmap directly: most desktop environments honor those files and all keyboard layouts you see in keyboard settings are actually from those XML files.

Creating custom keyboard layout

For example, I'm looking to add a new modified English (international AltGr dead keys) US layout with swapped r,R & t,T. I will name it XY swapped:RT English (international AltGr dead keys).

1. Create new symbols file:

   sudo nano /usr/share/X11/xkb/symbols/xy

    default  partial alphanumeric_keys
    xkb_symbols "basic" {
   
       name[Group1]= "XY swapped:RT English (international AltGr dead keys)";
   
       include "us(altgr-intl)"
   
    // my custom changes:
   
       key <AD04> { [        t, T,           ediaeresis,   Ediaeresis      ] };
       key <AD05> { [        r, R,           thorn,        THORN           ] };
   
   
       include "level3(ralt_switch)"
    };
   

   include "us(altgr-intl)" means it inherits all key from that layout only key overridden here.

   You may use Keyboard Layout Editor which is a GUI program that helps create or edit XKB keyboard layouts. Thanks to @Glutanimate

2. Add the new layout declaration to /usr/share/X11/xkb/rules/evdev.xml (copy & modify us layout section)

   Reference: Make new variant keyboard layout available in Settings?

   sudo gedit /usr/share/X11/xkb/rules/evdev.xml

    ...
    <layout>
      <configItem>
        <name>xy</name>
   
        <shortDescription>en</shortDescription>
        <description>XY swapped:RT English (international AltGr dead keys)</description>
        <languageList>
                 <iso639Id>eng</iso639Id>
                 <iso639Id>fra</iso639Id>
                 <iso639Id>ger</iso639Id>
        </languageList>
      </configItem>
      <variantList>
      </variantList>
    </layout>
    ...
   

3. Delete xkb cache.

    sudo rm /var/lib/xkb/*.xkm
   

   Notes:

   To load changes to the layouts menu simply restart gnome-keyboard-preferences; relaunching the window manager should not be necessary.

   There is a change in Ubuntu version 13.10 which causes the keyboard settings cache to not refresh after files in "/usr/share/X11/xkb/symbols" are modified. It looks like changes just don't get applied. To force the cache refreshing a one should delete *.xkm files from "/var/lib/xkb".

   ^{Reference: Howto: Custom keyboard layout definitions}

   or

    sudo dpkg-reconfigure xkb-data
   

   ^{Reference: Why did 13.10 break my custom keyboard layout?}

   

Reply to fix OP modifications

• (Update #1 wrong parent layout) You have modified xkb_symbols "pes_part_basic" which is in irwinxp file: that's ok.

  but xkb_symbols "pes" in irwinxp file still:

    include "ir(pes_part_basic)"
  

  which should be:

    include "irwinxp(pes_part_basic)"
  

• (Update #2 custom icon) If <shortDescription>en</shortDescription> changed to <shortDescription>xy</shortDescription>. So the new layout will distinct from En and it will appear as Xy.

  Most probably there will be no icon for it in ubuntu-mono. Then the indicator will dynamically generate new one which may not follow current theme.

  1. Copy any layout icons for dark/light mono themes:

      sudo cp /usr/share/icons/ubuntu-mono-dark/status/22/indicator-keyboard-En.svg /usr/share/icons/ubuntu-mono-dark/status/22/indicator-keyboard-Xy.svg
      sudo cp /usr/share/icons/ubuntu-mono-light/status/22/indicator-keyboard-En.svg /usr/share/icons/ubuntu-mono-light/status/22/indicator-keyboard-Xy.svg
     

  2. SVG files are just XML. Open then for editing and change text value from En to Xy:

      sudo nano /usr/share/icons/ubuntu-mono-dark/status/22/indicator-keyboard-Xy.svg
      sudo nano /usr/share/icons/ubuntu-mono-light/status/22/indicator-keyboard-Xy.svg
     

     Example:

      <?xml version="1.0" encoding="UTF-8" standalone="no"?>
      <svg width="22" xmlns="http://www.w3.org/2000/svg" version="1.1" height="22">
       <defs>
        <mask id="m">
         <rect y="0" x="0" style="fill:#fff" height="22" width="22"/>
         <text y="15.5" x="5" style="font-size:12;font-family:Ubuntu;font-weight:500;fill:black">Xy</text>
        </mask>
       </defs>
       <rect style="fill:#dfdbd2" mask="url(#m)" rx="2" height="20" width="20" y="1" x="1"/>
      </svg>
     

  3. Update theme cache:

      sudo update-icon-caches /usr/share/icons/ubuntu-mono-*/            
     

  4. Logout/login

     

Other Helpful References

• How to modify a keyboard layout in Linux (thanks to @Rmano)
• Building an XKB Keyboard (thanks to @Glutanimate)