This redirect script is here only so that the page name changes when you view the Main_Calendar. In RWD, if you just call a calendar, the page you are on does not change, the middle of the page just gets replaced with the calendar. At the teacher level, this is not a big deal but on a corporate or district / school level, it can be confusing to have a calendar appear on a page with an unrelated title.
This page, when hit by a browser will run the following redirect script and open the Main_Calendar immediately.
Text in purple indicates the path and name of the calendar
Text in Orange indicates variables you can modify