composer/composer — pull request #1812 by lphuberdeau (2013-04-19 00:01:38+00:00)
Title: Using ZipArchive when available in Zip Downloader

We have been running into issues in several environments in which the unzip command would extract files with unreadable files by the owner. Using ZipArchive when available produces more stable results.

Moreover, unzip is not available in all environments.