FrontendUser::setCookie() 

\nn\t3::FrontendUser()->setCookie($sessionId = NULL, $request = NULL); 

Set the fe_typo_user cookie manually.

If no sessionID is passed, Typo3 searches for the FE user's session ID itself.

When calling this method from a MiddleWare, the request should be passed with . This allows, for example, the global $_COOKIE value and the cookieParams.fe_typo_user in the request before authentication via typo3/cms-frontend/authentication in a separate MiddleWare must be set. Helpful if cross-domain authentication is required (e.g. via Json Web Token / JWT).

\nn\t3::FrontendUser()->setCookie();
\nn\t3::FrontendUser()->setCookie( $sessionId );
\nn\t3::FrontendUser()->setCookie( $sessionId, $request );

| @return void

public function setCookie( $sessionId = null, &$request = null )
{
	if (!$sessionId) {
		$sessionId = $this->getSessionId();
	}
	$jwt = self::encodeHashSignedJwt(
		[
			'identifier' => $sessionId,
			'time' => (new \DateTimeImmutable())->format(\DateTimeImmutable::RFC3339),
		],
		self::createSigningKeyFromEncryptionKey(UserSession::class)
	);
	$cookieName = $this->getCookieName();
	$_COOKIE[$cookieName] = $jwt;
	\nn\t3::Cookies()->add( $cookieName, $jwt );
}