This secret is more like a scavenger hunt, where you follow the steps to find the next coords, until the end.
That being said, I still felt it worthwhile to document the way you travel doing said mission.
The first step is to go to the enchant room, using .enchant to warp there. You can see there is some extra space behind the set up.
If you go really close, you can see an enderchest as well as a lectern.
Crouching reveals the first coords for the scavenger hunt!
The coords above lead to the bridge underneath the trade center.
Here are the new coords.
These coords lead to a lectern floating in the void past the waterfall. This one is tricky to capture.
Spamming screenshot while flying lets you capture the next coords for the scavenger hunt!
The coords from the floating lectern lead you back to the water tunnel that you find the barnacle NPC from the villager mission. Hidden behind vines.
Here are the coords for it
The final coords lead to a dead end however, up in the cherry tree
I have gone here multiple times and still have yet to see any changes such as a prize or another lectern with coords. Others have given up on this quest, so I have considered it dead.
