github port group

[Sean Farley]

> Ah, you're right, they did not. Now I get the same sums, if both files have not only the same name but also the same timestamp.
>
> So I guess what a service like bitbucket would have to do when it generates a tarball is to set its timestamp to the timestamp of the requested revision before gzipping it.

It might have been a result of this bug (which has been fixed but
caused tarballs to be regenerated):

https://bitbucket.org/site/master/issue/3402/zip-files-stale