This extension will detect when the user visits WotC's Gatherer website (https://gatherer.wizards.com). When a specific card's page is viewed there (usually an address such as https://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=<SOME_CARD_ID>) the user will be redirected to the corresponding page of the Scryfall service instead. This redirect is implemented on an HTTP event level meaning that you will not even go through Gatherer itself. Note that other Gatherer pages (e.g. homepage, search page) are unaffected by this redirect and can be visited normally. Source can be found at https://github.com/jathanasiou/ScryOne