I don't know if using lanterns below the "no air" level would be considered an exploit or not, but I thought I'd mention it.

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Idea is that you can't place cheap light sources in caves. Torches are very cheap. Glowstone is not.

Wanted you to check if glowstone is prohibited since it's not a new block

Are other light source blocks like glowstone blocked?

No. Lanterns are a new block, although they may actually be block entities. I didn't check. The lighting config is the default.

EDIT: Around "Torches" and "Campfire" I don't see anything of "block these light sources", and I don't recall anything like that in the config. I don't mind dropping the config in here if it would help, and I don't know of any other plugin I would be using that would have any impact. "Use case" expectations is that I would see something like the Campfire setting, just focused on lanterns. But has hard as hell it is to get iron, if a setting was in there to allow/ disallow lanterns, I'd likely allow them anyway. You STILL have to use up a precious ingot of ore for those, and I have to find a balance in the challenge to play.

Glowstone places without a problem Y<30 in Survival.

Ok, doesn't sound like an exploit then. Granted, it seems that lanterns are relatively cheap, but at least it requires a crafting table instead of player inventory. So idk - if lanterns are abundant in caves then perhaps this could be considered?

As long as you are happy with the balance, and my wife would make me allow lanterns anyway. 🤗 But I was surprised it worked.