composer/composer — pull request #686 by Seldaek (2012-05-13 20:58:48+00:00)
Title: Cache for Github metadata

This speeds things up quite substantially, and once enabled on Packagist I'd guess it will boost the import speed quite a bit as well for large repos with tons of tags/branches. It caches only data for commits to ensure that if anything changes, the cache is invalidated since a new hash would be generated.