wp-includes/class-wp-http.php:800Takes the arguments for a ::request() and checks for the cookie array.
$rarray public static function buildCookieHeader( &$r ) { // phpcs:ignore WordPress.NamingConventions.ValidFunctionName.MethodNameInvalid if ( ! empty( $r['cookies'] ) ) { // Upgrade any name => value cookie pairs to WP_HTTP_Cookie instances. foreach ( $r['cookies'] as $name => $value ) { if ( ! is_object( $value ) ) { $r['cookies'][ $name ] = new WP_Http_Cookie( array( 'name' => $name, 'value' => $value, ) ); } } $cookies_header = ''; foreach ( (array) $r['cookies'] as $cookie ) { $cookies_header .= $cookie->getHeaderValue() . '; '; } $cookies_header = substr( $cookies_header, 0, -2 ); $r['headers']['cookie'] = $cookies_header; } }Introduced in 2.8.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-wp-http.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.