(template_type)_template_hierarchy │ filter-hook │ WP 1.0

This filter is documented in wp-includes/template.php

Usage

add_filter( '(template_type)_template_hierarchy', 'wp_kama_template_type_hierarchy_filter' );

/**
 * Function for `(template_type)_template_hierarchy` filter-hook.
 * 
 * @param  $template_hierarchy 
 *
 * @return 
 */
function wp_kama_template_type_hierarchy_filter( $template_hierarchy ){

	// filter...
	return $template_hierarchy;
}

$template_hierarchy

-

Where the hook is called

return apply_filters( "{$template_type}_template_hierarchy", $template_hierarchy );

Where the hook is used in WordPress