iTunes Extras files (.ite) are used by Apple's iTunes application for storing multiple files (of different types) in to a single file. They are actually standard folders but with an appended .ite extension (so removing the .ite extension will allow you view the folders' contents).

They are used by iTunes so store website pages, so may contain anything from HTML etc through to images, audio and video. They can be found bundled with various products purchased via the iTunes store (movies for example).

iTunes is a multimedia shopping and media organization/playback tool developed by Apple.