An AS2PROJ file is a project file created by the open source Flash programming IDE, FlashDevelop. It contains project related information such as build settings, references to project source files, and options for generating the output .swf file. Every new project created in FlashDevelop is saved as an AS2PROJ file. You can change the settings for your project and all these changes are saved to AS2PROJ file.
AS2PROJ files can be opened with FlashDevelop.
AS2PROJ File Format
An AS2PROJ file is saved in XML file format that is a universal file format for exchange of information. It can be opened in any text editor such as Notepad, Notepad++ and Atom to examine the contents.