Is fullbright allowed?

No. Fullbright is considered cheating and is not considered to be purely cosmetic since it gives an advantage to players who use it (easier to find ores when mining, no need to craft torches or other lighting, easier to defend from mobs at night, etc.) However, fullbright is difficult to moderate and almost impossible to detect automatically. For these reasons, if you decide to use it - you will almost certainly get away with it.

Having this small advantage over other players may not seem like much, but it is unfair nevertheless. Since it is pretty much impossible for our moderation team to stop you, we simply ask you to be considerate. Having any sort of unfair advantage just takes away from the experience we are trying to create on Hellabread and makes the game less rewarding for you in the long-run.

So we say no, and this is why. But it's up to you.