[mirabilos]

Github doesn’t, it just requires that of its users (that, or to not upload any copylefted works, or works under licences requiring attribution, which contain work from people who have not agreed to waive those requirements for Github).

[hl5]

If Github can continue to use and distribute free software without violating the terms of the license then why demand additional rights? I don't get it.

Google doesn't attribute links to free software appearing in it's search results. Github doesn't need special rights to do it.