Not a post saying "Update the wiki!", I mean this can be used to talk about items not yet added to the wiki, for people who want to craft/farm for certain items

Currently, I'm in the circumstance where I desperately need to use the wiki, yet nothing I need has been added yet. Most important thing is the Abyss, as I need Abyss Fragments, the wiki says to get them from chests above the city, but there's an issue: They're all requiring a key I have no way of obtaining because I don't know if it's a drop, craft, or rare find. Does anyone know where to get this key?