birdfont.xml
<?xml version="1.0" encoding="UTF-8"?>
<mime-info xmlns="http://www.freedesktop.org/standards/shared-mime-info">
<mime-type type="application/birdfont">
<comment>BirdFont file</comment>
<comment xml:lang="en">Font</comment>
<magic priority="100">
<match type="string" value="<font" offset="1"/>
</magic>
<glob pattern="*.bf" />
<alias type="application/birdfont"/>
</mime-type>
</mime-info>