Most OS X applications are usually a folder that behaves like an executable (has a custom icon, will run the app when you double click on it). So no, it's not r

Most OS X applications are usually a folder that behaves like an executable (has a custom icon, will run the app when you double click on it). So no, it's not running an installer script, it's just copying a folder, and the app runs with just what's in the folder, no install process needed. For things that require changing system components, other apps etc. there is a normal install wizard.