Fix for DjVu files being detected as MIME type image/vnd.djvu instead of image/vnd.djvu+multipage

override.xml

<?xml version="1.0" encoding="UTF-8"?>
<mime-info xmlns="http://www.freedesktop.org/standards/shared-mime-info">
  <!-- Created on 2019-05-15 to fix a reappearance of this bug: -->
  <!-- https://bugs.launchpad.net/ubuntu/+source/djvulibre/+bug/1778088 -->
  <!-- (DjVu seen as image/vnd.djvu instead of image/vnd.djvu+multipage) -->
  <!-- https://twitter.com/gro_tsen/status/1128645721614356480 -->
  <!-- Run "update-mime-database ~/.local/share/mime" after creating this. -->
  <!-- Use "xdg-mime query filetype some-file.djvu" to test. -->
  <!-- - David A. Madore -->
  <mime-type type="image/vnd.djvu+multipage">
    <comment>DjVu image</comment>
    <alias type="image/x-djvu"/>
    <magic priority="99">
      <match value="AT&amp;TFORM" type="string" offset="0">
        <match value="DJVU" type="string" offset="12"/>
      </match>
      <match value="FORM" type="string" offset="0">
        <match value="DJVU" type="string" offset="8"/>
      </match>
    </magic>
    <glob pattern="*.djvu"/>
    <glob pattern="*.djv"/>
  </mime-type>
</mime-info>

The override.xml file in question should be placed in ~/.local/share/mime/packages/ and then run "update-mime-database ~/.local/share/mime" (to create or regenerate ~/.local/share/mime/mime.cache).