An old Bukkit plugin that adds dungeons, ruins and a bunch of random structures to your world. It has a loot levelling system and you can find the craziest gear you could imagine.
Was linked this project by someone, but noticed you're using CC Non-Commercial.
This isn't really a great license for software, and it's easy to argue that almost every Minecraft Server is commercial. (The only way you can classify as Non-Commercial is if you do not take any form of payments nor run any advertisements on your website unless you register as an official non-profit)
I suggest switching to a more common software license, such as GPL, MIT or Apache (I Recommend MIT)
I tried to compile with the latest referenced libraries and it still threw errors about chunk populate, what other libraries are needed to compile this plugin besides the ones in the EXTERNAL_LIBRARIES.md?
While the plugin is working fine, that actually may be the problem. I'm not sure if this can be avoided, but it should be noted that worlds that were created prior to 1.13 will regenerate existing chunks as if they were new. This causes MagicLoot to generate structures into chunks that existed before, destroying any builds that were there.
I've temporarily removed this plugin; the only solution from my end is to explore my world until I've found all my existing structures, but this is quite time consuming.