A Vary: Accept-Language should be added if the url returns different content based on the Accept-Language by the User-Agent. Since there is no Cache-Control: private, a result could be cached by some TLS terminating proxy server.
See Server-driven content negotiation - MDN.
Both would steer search engines in better direction to actually link to the correct URL. It could now happen that a search engine returns an English text, and the users clicks and gets the Dutch text, and the reverse. Although the reality is that the apex defaults to English, so internet.nl is seen by search engines as en.internet.nl.
A
Vary: Accept-Languageshould be added if the url returns different content based on theAccept-Languageby the User-Agent. Since there is noCache-Control: private, a result could be cached by some TLS terminating proxy server. See Server-driven content negotiation - MDN.Another thing would be to include more headers:
Both would steer search engines in better direction to actually link to the correct URL. It could now happen that a search engine returns an English text, and the users clicks and gets the Dutch text, and the reverse. Although the reality is that the apex defaults to English, so internet.nl is seen by search engines as en.internet.nl.
This could be (almost) pure nginx.