A file with .an extension is an Adobe Edge Animate project file that contains information about the animation. A .html file is created when the project is saved which contains the references to the associated .css and .js files generated by Adobe Edge Animate. The AN file is saved along with these files that can be used to open the project file. Adobe edge animate can be used as an alternative to creating animated webpages using Adobe Flash, which is no more supported by browsers.
AN File Format
AN files are stored to disc in plain text file format and can be opened in text editors of viewing their contents.