When I used to run websites in the past, one of the most popular features was the Referer Log which would show how people had found your site. You'd see sites that were linking to you, and search terms people used to find you.
I was sure that someone would have asked this before, but can't find any references whatsoever?
I seem to have quite a few people visiting my new wiki, but have no idea where from.
As Tupka217 said, you can ask staff. However, they are not likely to share that information with you as it is probably critical to their revenue stream. They aren't going to want to share critical revenue-related information unless it is really necessary. That is the whole reason why Special:Analytics shows you 30-day totals/averages for the last 30 days instead of daily numbers since the wiki's creation.
And I've seen some of that data, it's wouldn't have specific website urls. More likely n% via search engines, n% via other wikis, n% via third part links etc. There's simply too much data to be more specific.
The point is, wiki admins are not site owners - Fandom is. Sometimes Fandom look like a site host, because they give local admins some amount of freedom with their local policies and even with custom CSS and JS. But in fact, Fandom owns all the wikis, and keep total control over everything. Fandom's customers are not the local admins. Fandom's customers are the site visitors who watch their ads, while the editors and admins are more like volunteers who enjoy developing the wiki as a hobbie.