"Blorb" is a nonsense word from a popular early 1980s work of IF called Enchanter where it was the name of a magic spell whose purpose was to "safely protect a small object as though in a strong box." In the late 1990s, the name was borrowed for a standard format for what might be called the wrapping and packaging of IF. A typical Blorb archive produced by Inform contains the "story file" -- the actual program for the game -- together with its library card and cover art.

-- Graham Nelson in Writing with Inform

This program uses that cover art to generate thumbnail previews for GNOME's file manager. It works with Nautilus (in GNOME 2 and GNOME 3) and Unity (in Ubuntu 10.10+).