Source

File: wp-includes/rest-api/class-wp-rest-response.php

public function link_header( $rel, $link, $other = array() ) {
		$header = '<' . $link . '>; rel="' . $rel . '"';

		foreach ( $other as $key => $value ) {
			if ( 'title' === $key ) {
				$value = '"' . $value . '"';
			}

			$header .= '; ' . $key . '=' . $value;
		}
		$this->header( 'Link', $header, false );
	}