Comment 25 for bug 331311

Response from my merge request:

"Thanks a lot for the effort Andrew, but that approach would just be a temporary fix we need to undo later. These icons belong to the icon-theme proper. Ripping them out and stuffing them in notify-osd is not wise (not to mention that the Tango/GNOME folks would tar and feather us for such a solution :). The remaining icon-set for other themes (GNOME/Tango, hicolor) - to satisfy the new names in the icon-theme namespace - are being worked on right now. We are also discussing this with some of the upstream people responsible vor GNOME- and Tango-icons."

So it sounds like they are planning on submitting icons upstream to GNOME....