What stays in the tab
The site keeps one thing: the reader's choice of a light or dark theme. That choice sits in this browser tab and is gone once the tab is closed. To show which venues are lit or dark, the tools read the device clock against published hours in Atlantic Time, and nothing else. Nothing is sent anywhere.
Paid links, marked Ad, appear only on the home page. Each one opens the partner site in a new tab without passing along the page the reader came from. Inner pages carry none.