It is possible to download extensions in ZIP format from the WMF repo using a link like this:
http://git.wikimedia.org/zip/?r=mediawiki/extensions/FooBar.git&h=someTa...
However, this will produce a package with the extension's files in its root folder. An unsuspecting user will probably simply extract this package into the .../extensions folder with all its files ending up there instead of in the extensions subfolder.
The ExtensionDistributor will provide correctly built packages, but it is apparently only working on MW release tags, e.g. REL1_26.
Is there any way to download correctly built packages with tags other than the MW relases?
Stephan