/wp-content/themes/twentyfifteen/inc/

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	back-compat.php    [source] [83 lines]	Twenty Fifteen back compat functionality Prevents Twenty Fifteen from running on WordPress versions prior to 4.1, since this theme is not meant to be backward compatible beyond that and relies on many newer functions and markup changes introduced in 4.1.
	block-patterns.php [source] [68 lines]	Block Patterns
	custom-header.php  [source] [380 lines]	Custom Header functionality for Twenty Fifteen
	customizer.php     [source] [811 lines]	Twenty Fifteen Customizer functionality
	template-tags.php  [source] [290 lines]	Custom template tags for Twenty Fifteen Eventually, some of the functionality here could be replaced by core features.