AppData questions

[Michael Schwendt]

I'm trying to follow what's happening related to gnome-software and the
.appdata.xml files. There is a growing number of mails, but I cannot find
any message that points out what the file

  # rpm -qf /usr/share/app-info/xmls/fedora-20.xml.gz
  gnome-software-3.10.3-1.fc20.x86_64

does.

For "Audacious" it specifies several details, such as an icon included
in the gnome-software package and MIME types. How to update or override
those details? The file contains a summary "Listen to music". So far, I'm
unable to install an AppData file for Audacious that would be recognised
by gnome-software. The installed file validates fine. Still, gnome-software
only displays "Listen to music". Is there a hidden cache file in some place?
Or a remote database that is updated from time to time?
I've tried to "Remove" Audacious via gnome-software, then reinstall it,
but that didn't fix it either. [1]  How to determine why the file is not
recognised?

What is the recommended procedure to test new .appdata.xml files?
Where does gnome-software find those files? I mean, for uninstalled packages
the files are not available. Not even the .desktop files. There must be
some method that recognises such files in repo metadata and extracts them,
or else gnome-software could not know about the file contents.


Is a screenshot mandatory? The current test-update for Audacious includes
an .appdata.xml file where the screenshot section is commented out. Is that
permitted?


I've noticed an AppData file has been contributed to Soundconverter upstream.
Since the Fedora packages of Soundconverter lead to many changes upstream,
I've merged the file, but the specified screenshot does not display. The
validator finds a problem:

  /usr/share/appdata/soundconverter.appdata.xml 1 problems detected:
  • attribute invalid     : <screenshot> width was too small

The contributed file does not set any attributes width or height.


[1] There's a related bug in gnome-software, btw, since a consecutive Remove
and Install does not work.  https://bugzilla.redhat.com/1027183