SUPEE-3941 provides the following fixes for Magento Downloader:
- When you install a community-created translation package, the translation provided by the package overwrites any existing translations for the same items. This enables you to more easily install packages with translations.
- To improve security, Magento Connect now uses HTTPS by default to download extensions, rather than FTP.
- Extension developers can now create an extensions with a dash character in the name. Merchants can install those extensions without issues.
- Magento administrators who attempt to install an extension with insufficient file system privileges are now informed. Typically, the Magento Admin Panel runs as the web server user. If this user has insufficient privileges to the your Magento install dir
/app/code/communitydirectory structure, the Magento administrator sees an error message in the Magento Connect Manager.