Upgrader Skin for Automatic WordPress Upgrades.

Determines whether the upgrader needs FTP/SSH details in order to connect to the filesystem.

Bulk Plugin Upgrader Skin for WordPress Plugin Upgrades.

Bulk Theme Upgrader Skin for WordPress Theme Upgrades.

Generic Bulk Upgrader Skin for WordPress Upgrades.

Core class used for updating core.

Core class used for handling file uploads.

Core class used for updating/installing language packs (translations) for plugins, themes, and core.

Translation Upgrader Skin for WordPress Translation Upgrades.

Plugin Installer Skin for WordPress Plugin Installer.