I found a little easter egg. It turns out it's not unknown on these forums, but it wasn't in the Lancet Jades guide, and I found it all by myself
It's not a very big easter egg, its just a book named 'crumpled note' which as 'HIC SUNT DRACONES' as the only contents. Incremental spoilers:
I found it because I was thinking about statues and pigeons. (Really!)
If you search these forums there's a thread in german with a picture of the location.
Its on top of the humongous statue near the entrance from broken valley in orobas fjords. But honestly, now that you've read this its not worth picking up.