The gnome mime database thinks OTF files are some kind of ODF file (as
documented in the ODF spec).
However the OTF extension has long been used for OpenType fonts with CFF data,
and it's easy to check font OTF files massively outnumber ODF OTF files in the wild (and are likely to continue as OTF is used for pretty much every new font nowadays)
Therefore the default should be switched to font file.
Even OO.o uses the OTF moniker for font files
(for example I count ~ 30 packages including one or many OTF font files in Fedora, and none including ODF OTF files)
All the mime-types associated with *.otf have magic data associated, so front-ends should be able to detect which is which by using magic in case of conflict.
Adding weight for one or the other would cause more problems than it would solve. So file a bug against the applications that fail to detect the files correctly instead.
*** Bug 20603 has been marked as a duplicate of this bug. ***
Over on Launchpad, Seb Bacher is saying this isn't a Nautilus/file-handling bug.
Over here, it's not a mime-type bug.
It's got to be one or the other. So which is it?
Copypasta from one of my comments on the Launchpad bug:
This is not a problem with the current Gnome Font Viewer, as is easily proven:
1. Find an OTF font file on your system.
2. If you just double-click on it, OpenOffice attempts to open it, and fails.
2. Right-click the OTF, go Open With -> Open With Other Application -> Font Viewer
3. Font Viewer opens and displays the OTF preview just as it should, exactly like a TTF is shown.
So I'm not sure how this bug can be Invalid against all three of the targets currently listed. It's should be valid against at least one, if not all.
(The above was all done on Ubuntu 9.04)
It is a bug in the file managers. File a bug against them.
we need to add a glob for *.otf to the font mime type too, since the current agreed-on matching algorithm only looks at magic to disambiguate if there is a glob conflict.
I tested locally that adding the glob makes otf fonts show up correctly in nautilus.
* freedesktop.org.xml.in: Add *.otf as a glob for
OpenType fonts so file managers use magic to check
for fonts vs. OO.o documents (Closes: #20854)
on Dec 06, 2016 at 17:56:26.
(provided by the Example extension).