.AS2PROJ File Extension

Project file created by FlashDevelop, an free and open source development IDE commonly used for Flash programming; saved in an XML format and contains build settings, references to project source code files, and output .SWF options.

ActionScript 2 projects can be created by choosing Project → New Project in the software. The AS2PROJ file and the other project files and directories are saved to the directory that you specify in the New Project window that appears.