I just found another oddity. Searching for "test" yields a couple strange results: One for Divinity: Original Sin 2, and the other for Planet Nomads. The titles don't appear to contain "test" at all, and the two games in question (both of which are priced at "TBA") don't appear to have game cards; clicking on one of them doesn't do anything, so why are those two games showing up? (Of the other 4 results, 2 contain a word containing "test" in the title, and the other 2 are by a company that has the word "test" in its name.
I note that the original Divinity: Original Sin did not show up in the search results.
Perhaps there exists a placeholder gamecard, inaccessible by normal means, but scanned by the search tool, that contains the word "test"? (I'm guessing it's some placeholder text here.)