I'm working on converting the Crystal SVG icon set for use with XFCE. How do I figure out what names to give the icons?
After some digging through the source code:
For things other than ordinary files, http://live.gnome.org/GnomeArt/Tutorials/IconThemes covers the naming. For files, name it after the MIME-type in the form <media>-<subtype>.svg (or .png); the file /usr/share/mime/globs has the mapping between extensions and MIME-types.
If it can't find an icon for a given MIME-type, it will fall back to, in order:
There are also media-specific fallbacks: for example, if it can't find text/x-csrc, it will use the icon for text/plain instead.