Black Book Footnote

[Grieg]

I was doing the Filament and Filigree "Dungeon", and right at the end, on the left side of the platform with the reward book, there is a book named "Chapter VI Footnote".
When I open it, I get transported to another area with three Soul Gem Receptacles. When I interact with them, a black soul gem from my inventory is added to them. There is also a Scrye, like the ones you use in other Black Books to open gates etc. however, interacting with it does nothing.
Does anyone have a clue what this is? I couldn't find a single reference to this anywhere and in playthrough videos this footnote book doesn't even exist.

[Friday the Thirteenth]

I see I'm not the only one who sees this...
Based on the console ID I'm guessing it's added by a mod, but I don't know which one..

[Bomb Bloke]

If memory serves, the first two digits of the ID can be used to work out which ESM/ESP/whatever it's coming from. Compare those to the mods in your load order - try checking some "vanilla" Dragonborn DLC item IDs to see what I mean. If the third mod in your list is the Dragonborn ESM, then Dragonborn item IDs should start with something like 03.

Edit:

Actually, never mind. Looks like it's this[sites.google.com] from the "Konahrik's Accoutrements: Dragon Priest Armory" mod.

[Ranxaeroth]

On the mod page is a link to its homepage. It describes in detail all aspects of the mod. For this area, each alter has an associated mask. Pace mask, then soul gem, then activate Scrye to resurrect that dragon priest. Etc etc.