I don't think they are. You have to find another game made with them and click the link in the More Information box. And I see what you mean now. New tools and engines are added very slowly. Even fairly well known apps aren't there.
That's what I'm curious about. I wanted it listed there as an engine. I only created the itch.io page because I thought perhaps that would help it actually get published. I added a download file.
That will allow your project page to get indexed, but redonihunter is right. I misunderstood your question. It won't help your engine get listed as an engine. Sorry about that.
