rest_output_link_header() │ WP 4.4.0

Sends a Link header for the REST API.

No Hooks.

Return

null. Nothing (null).

Usage

rest_output_link_header();

Changelog

Since 4.4.0 Introduced.

rest_output_link_header() code WP 6.7.1

wp-includes/rest-api.php 
function rest_output_link_header() {
	if ( headers_sent() ) {
		return;
	}

	$api_root = get_rest_url();

	if ( empty( $api_root ) ) {
		return;
	}

	header( sprintf( 'Link: <%s>; rel="https://api.w.org/"', sanitize_url( $api_root ) ), false );

	$resource = rest_get_queried_resource_route();

	if ( $resource ) {
		header(
			sprintf(
				'Link: <%1$s>; rel="alternate"; title="%2$s"; type="application/json"',
				sanitize_url( rest_url( $resource ) ),
				_x( 'JSON', 'REST API resource link name' )
			),
			false
		);
	}
}