HTTP Referrer and URL are included under Navigation in Google Tag Manager because they both provide important information about how users are navigating through a website.
HTTP Referrer is the URL of the previous webpage that the user visited before arriving at the current page. This information is useful for tracking the source of traffic to a website and analyzing user behavior.
URL, on the other hand, provides the current page's URL or the page that the user is currently viewing. This information can be used to trigger tags or track specific user interactions on a page.
Together, these variables can provide insights into how users are entering and navigating a website, which can help marketers optimize the user experience and improve website performance.