[tde-users] In a TDM theme's xml file, what does @@@TDEBACKGROUND@@@ point to?

I'm trying to write a custom theme file for TDM, using os_enterprise theme as an example. It contains | <greeter> | <item type="pixmap" > | <normal file="@@@TDMBACKGROUND@@@" /> | : to define the login screen's background. I've looked through the various TDE handbooks and poked around on the wiki, but nothing mentions this symbol. (In fact, the only page in the wiki that I found that discusses the internals of theme files seems to be out of date, since it talks about Theme.rc files, whereas the control file in each /opt/trinity/share/apps/tdm/themes subdirectory is an xml file. When the os_enterprise theme is active its display looks like its preview.png, even if the background.png file is different; so what is @@@TDEBACKGROUND@@@ pointing to? Leslie