What is the criteria for the "modded" server tag?

I do not have any mods installed on my server, just an extensive server.cfg file, yet my server is listed under the modded servers. Why is this? When my server started out in the beginning of February, it wasn’t listed there. Over time, I have added different settings, but I know stuff like decay or airdrop players don’t mark the server modded.

What server settings mark a server as modded?

Edit:

Testing this out after I posted this, I removed the following settings from my server.cfg:

My server is now listed under Community. One of these seems to mark the server as modded.

Edit2:

Hours later, after my server performs a scheduled restart, it’s back in the Modded section again. Really?