WordPress \ ACF : Add "Nowhere" as a location to "Page Type" rules.

wp-acf-location-nowhere.php

<?php

/**
 * Filter: Add "Nowhere" as a location to "Page Type" rules.
 * 
 * Useful for third-parties seeking to dynamically embed
 * the field group in a non-traditional manner.
 *
 * @used-by Filer: 'acf/location/rule_values/page_type'
 * @param array $choices
 * @return array $choices
 */

function location_page_type_rule_values( $choices = [] )
{
	// Add "Nowhere"
	$choices[''] = __('None');

	ksort( $choices );

	return $choices;
}

add_filter( 'acf/location/rule_values/page_type', 'location_page_type_rule_values' );