Doorway page
A doorway page is created to capture a query without providing original content: the same text reproduced city by city, or gateway pages that redirect to a single destination. Google classifies them as a violation of its policies.
In practice
The swap test exposes them: replace the city name throughout the text — if the page remains true, it is a doorway. A genuine local page cites facts that would not survive the swap: real distances, neighborhoods, territorial constraints. That is the threshold our engine enforces on every generated page.