Actually, that is incorrect.
When a user zips up a folder for packaging on OS X (Apple’s Operating System), by clicking compress through the contextual menu, the resulting archive (zip folder) has an extra folder called _MACOSX. It is created by Apple so spotlight can search the zip directory easy and faster.
This folder can be safety deleted or the developer can repackage on their Mac using dedicated archiving software. (Anything other than Mac’s built in option)
To other commenters, be sure when responding to posts you have actually examined the files in question, or start of by saying you are simply postulating as others may quickly think you know what you are talking about and not continue to research the real problem. Good luck!