Paywall or Cookie Paywall?

Some websites were not presenting the same interface, according to annotators. We guess also that some were presenting cookie paywalls and others some just regular paywalls. I think it's called personalizing pricing. It's basically the idea that you would present a different product according to like some tailored features. If you're browsing with Firefox or if you're browse with a Chrome for instance you won't have the same presentation. This is also something that you would like to know how.