WordPress Media Library doesn’t allow you to upload any file you want, you are limited to a small set of types.
With the plugin “WordPress Extra File Types” you extend the default list of file types adding more than 680 extensions, presented and selectable in a dedicated administration page found under “Settings” menu.
– ver 0.3.0: added .dot extension and a new admin section that gives administrators a way to configure their own extra file types
– ver 0.2.4: removed .bid, added .bld
– ver 0.2.3: added .m4r file type
– ver 0.2.2: added .bid file type
– ver 0.2.1: added .msp and .msu file types
– ver 0.2 : added 687 file extensions, added administration page
– ver 0.1 : initial release, file extensions supported .txt, .7z, .bz2, .gz, .tgz, .txt, .xz, .zip