Calendar.php doesn't have the code that creates the calendar... it calls another encrypted file that creates the output necessary.
As for what you want to do, we've already accounted for that and provide you two ways of accomplishing it.
1- If you want to remove it from all normal mode calendars, in the Setup Manager, under the Navigation section, just disable it.
2- If you only want one calendar to not have the navigation, just before the require, add
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