It all seems quite scammy. They claim it's opt-in, but as a Brave user I can't find the option to opt-in or opt-out.

They look the searches you do at Google and other search engines. The search terms and the results you click on gets sent their way, including metadata from the page.

The content itself is downloaded by their bot (more like a fetcher). That bot has the user agent of a regular browser, so you won't see it.

You also can't specifically block their fetcher. It only adheres to disallow *.