An XAL file contains an asset list for a game using the Exient XGS Engine, including Angry Birds Go! and Angry Birds Transformers. It contains a list of references to various assets used by the app, such as effects, animations, and activities.

XAL files are not meant to be opened by a user. The XAL files are packaged with games and are referenced by the game to load the appropriate asset. You will most likely see XAL files with the assets.xal filename. However, you may also see the assets.xal_remote file for CDN downloaded assets, assets_mist.xal file for Mist Rovio CDN assets, and cache_assets.xal file for cached assets.