Extensions currently cannot be downloaded
I should add that I'm try to get the Cite extension for 1.15: http://www.mediawiki.org/wiki/Special:ExtensionDistributor?extdist_extension=Cite&extdist_version=branches%2FREL1_15&extdist_submit=Continue
Same with the Cite Extension, seems to be a problem across all extensions being downloaded. Hopefully this will be resolved soon.
I've now added a link in the Template:WikimediaDownload template to making a Git snapshot. The only downside with this is the fact that the snapshot will turn out to be a tar.gz instead of a zip file, but hey, it works at least! This is now visible on all extensions which are hosted on the MediaWiki repository, one just needs to click the Git link next to Download snapshot.