Fontconfig errors in Ubuntu 22.04.3 LTS

[a2geek]

Clock signal was not launching on Ubuntu. From the command-line:

$ clock-signal 
QSocketNotifier: Can only be used with threads started with QThread
Using Wayland-EGL
/usr/share/libdrm/amdgpu.ids: No such file or directory
Fontconfig warning: "/etc/fonts/conf.d/10-hinting-slight.conf", line 4: unknown element "its:rules"
Fontconfig warning: "/etc/fonts/conf.d/10-hinting-slight.conf", line 5: unknown element "its:translateRule"
Fontconfig error: "/etc/fonts/conf.d/10-hinting-slight.conf", line 5: invalid attribute 'translate'
...
Fontconfig error: "/etc/fonts/conf.d/90-synthetic.conf", line 6: invalid attribute 'xmlns:its'
Fontconfig error: "/etc/fonts/conf.d/90-synthetic.conf", line 6: invalid attribute 'version'
Segmentation fault (core dumped)

Looking at that file:

$ cat /etc/fonts/conf.d/10-hinting-slight.conf
<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
  <its:rules xmlns:its="http://www.w3.org/2005/11/its" version="1.0">
    <its:translateRule translate="no" selector="/fontconfig/*[not(self::description)]"/>
  </its:rules>

  <description>Set hintslight to hintstyle</description>

  <match target="pattern">
    <!--
      This configuration is available on the major desktop environments.
      We shouldn't overwrite it with "assign" unconditionally.
      Most clients may picks up the first value only. so using "append"
      may simply works to avoid it.
    -->
    <edit name="hintstyle" mode="append"><const>hintslight</const></edit>
  </match>
</fontconfig>

All I can figure from googling is that CLK may be linked against an older version of Fontconfig?

$ cat /etc/lsb-release 
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=22.04
DISTRIB_CODENAME=jammy
DISTRIB_DESCRIPTION="Ubuntu 22.04.3 LTS"

[a2geek]

Version of CLK:

$ snap list clock-signal
Name          Version   Rev  Tracking       Publisher  Notes
clock-signal  23.10.29  304  latest/stable  tomharte   -