wp_remote_retrieve_header( array|WP_Error $response, string $header )

Source

File: wp-includes/http.php

function wp_remote_retrieve_header( $response, $header ) {
	if ( is_wp_error( $response ) || ! isset( $response['headers'] ) ) {
		return '';
	}

	if ( isset( $response['headers'][ $header ] ) ) {
		return $response['headers'][ $header ];
	}

	return '';
}