Installation went through well from github but https://mytrezor.com/ also times out for me so there is the end of the testing.

Actually http://mytrezor.com/ works and said "Trezor Browser Plugin is succesfully installed" (there is a typo in "succesfully"). Probably the extension HTTPS Everywhere redirected to HTTPS, but if I enter http://mytrezor.com/ the plugin loads fine.

Tested it on a w7x64 on FF and chrome