Comment 7 for bug 1038679

Now that I am back in front of my laptop, here is the error message I am seeing, which has slight differences from the OP (same message, whether run under sudo or not):

alistair@w201386:~$ sudo software-properties-gtk
Fontconfig warning: "/etc/fonts/conf.d/65-droid-sans-fonts.conf", line 103: Having multiple values in <test> isn't supported and may not works as expected
Fontconfig warning: "/etc/fonts/conf.d/65-droid-sans-fonts.conf", line 138: Having multiple values in <test> isn't supported and may not works as expected
Fontconfig warning: "/etc/fonts/conf.d/69-language-selector-ja-jp.conf", line 141: Having multiple values in <test> isn't supported and may not works as expected
Fontconfig warning: "/etc/fonts/conf.d/69-language-selector-zh-tw.conf", line 79: Having multiple values in <test> isn't supported and may not works as expected
Fontconfig warning: "/etc/fonts/conf.d/90-fonts-nanum.conf", line 9: Having multiple values in <test> isn't supported and may not works as expected
Fontconfig warning: "/etc/fonts/conf.d/90-fonts-nanum.conf", line 22: Having multiple <family> in <alias> isn't supported and may not works as expected
Fontconfig warning: "/etc/fonts/conf.d/90-fonts-nanum.conf", line 22: Having multiple <family> in <alias> isn't supported and may not works as expected
Fontconfig warning: "/etc/fonts/conf.d/90-fonts-nanum.conf", line 22: Having multiple <family> in <alias> isn't supported and may not works as expected
Fontconfig warning: "/etc/fonts/conf.d/90-fonts-nanum.conf", line 26: Having multiple <family> in <alias> isn't supported and may not works as expected
Fontconfig warning: "/etc/fonts/conf.d/90-fonts-nanum.conf", line 31: Having multiple values in <test> isn't supported and may not works as expected
Fontconfig warning: "/etc/fonts/conf.d/90-fonts-nanum.conf", line 40: Having multiple values in <test> isn't supported and may not works as expected
gpg: /tmp/tmpkgyuia/trustdb.gpg: trustdb created
Traceback (most recent call last):
  File "/usr/bin/software-properties-gtk", line 103, in <module>
    app = SoftwarePropertiesGtk(datadir=options.data_dir, options=options, file=file)
  File "/usr/lib/python3/dist-packages/softwareproperties/gtk/SoftwarePropertiesGtk.py", line 180, in __init__
    self.show_drivers()
  File "/usr/lib/python3/dist-packages/softwareproperties/gtk/SoftwarePropertiesGtk.py", line 1280, in show_drivers
    widget = Gtk.Label("{}: {}".format(self.devices[device]['vendor'], self.devices[device]['model']))
KeyError: 'vendor'