.XCODEPLUGIN File Extension
What is an XCODEPLUGIN file?
Plugin used by Apple Xcode, an IDE used to create iOS and OS X apps; contains data referenced by Xcode to extend the application's capabilities, such as a "Clean Up Whitespace" menu item that removes unnecessary end of line white space from text files.
XCODEPLUGIN files should be installed in the ~/Library/Application Support/Developer/Shared/Xcode/Plug-ins directory. If the pathway does not exist, create it. Restart Xcode after installation to see the plugin functions appear in the application.
NOTE: The "xcodeplugin" extension was used by Xcode 3, but was replaced with the .DVTPLUGIN file in Xcode 4.