Freedesktop.org has a spec on detection that seems quite good. Unfortunately registration for programs to execute this mime type is elsewhere and so are the icons for this type. Interestingly the
mimetypes/ directory in the icon schemes doesn't just contain image files with the mime type name (correct me if I'm wrong!). So you have to register a mime type to an image name which seems redundant. Freedesktop.org also seems to be working on at least some of these issues.I was just googling my references and I think I want to read this.
In the process I've found a bug in the freedesktop.org MIME database or Nautilus (or both) - PGN files don't get detected as application/x-chess-pgn so Nautilus wont suggest glChess to execute them. It took me a long time to realise
update-mime does not update the database Nautilus uses (use update-mime-database /usr/share/mime).Oh and if anyones noticed there's still a rogue
import dbus in glChess 0.9.8. It wont cause any problems if you have the python dbus bindings but it's an unintended dependency that will not be in 0.9.9.