Fonts in system tray?

How does Weather Watcher get its list of fonts to choose from for the system tray icon? I always just assumed it took the installed system fonts, but I just installed a new font that I thought would be great for the sys tray and its not showing up as an option. I also notice that there is a “fonts.ww” file, but I don’t know what that does. Any help would be appreciated. Thanks!