How to display Stripe checkout in local language?

Stripe documentation says it does have a localised (Polish, in my case) checkout. But how do I force Ghost(Pro) to display it in a language other than English? I have set my localisation variable in settings to pl, but nothing seems to work.

Stripe will localize the checkout based on the location passed by your browser. Is the checkout showing as English when requesting it from within Poland?

You can spoof your location by going to the Sensors menu in Chrome Dev Tools and choosing a different location and then refreshing Stripe checkout.

Tried that on several browsers. Everything is in English.