The icons are mostly derived work from other icons. As such they are
licensed accordingly to the original license:

    GV: Gael Varoquaux: BSD-like 

Unless stated in this file, icons are work of enthought, and are released
under BSD-like license.
Files and orginal authors:
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          closed_folder.png | GV
               document.png | GV
            open_folder.png | GV