bower/bower — pull request #1442 by luckysw (2014-07-30 09:44:51+00:00)
Title: Added .zip MIME type (e.g. the default served by Windows/IIS)

Just found that .zip dependencies served behind IIS contains an unrecognized (but standard, it seems) MIME header.
Just adding that 'x-zip-compressed' to the list of known types fixes the issue.
Not sure about the other package MIME types, so I've left it as is.
Thank you,
Luciano