I noticed that indexing disappeared right when a user encouraged other users to report the game, claiming it contained a Trojan. But instead of investigating the issue, my game was simply removed from indexing.
Let me explain: my game is made using the Godot engine, which has a fairly common problem. If the game was exported as a single executable executable file, antivirus software would complain about a Trojan. But there was no Trojan.
Here are the sources of this problem:
https://www.reddit.com/r/godot/comments/1ln46ng/game_flagged_as_a_trojan_virus/
https://www.reddit.com/r/godot/comments/1h1nwsu/people_getting_viruses_from_fake_godot_repos/
https://github.com/godotengine/godot/issues/45563