_add_template_loader_filters() WordPress Function

function _add_template_loader_filters() {
	if ( ! current_theme_supports( 'block-templates' ) ) {
		return;
	}

	$template_types = array_keys( get_default_block_template_types() );
	foreach ( $template_types as $template_type ) {
		// Skip 'embed' for now because it is not a regular template type.
		if ( 'embed' === $template_type ) {
			continue;
		}
		add_filter( str_replace( '-', '', $template_type ) . '_template', 'locate_block_template', 20, 3 );
	}

	// Request to resolve a template.
	if ( isset( $_GET['_wp-find-template'] ) ) {
		add_filter( 'pre_get_posts', '_resolve_template_for_new_post' );
	}
}