According to the Tibia wiki, the only book or document added in this update is Rita's Letter (Book), a letter from Rita about a mysterious treasure, but it doesn't explore anything related to the new area of Rascacoon.
There is an observation note on the Tibia wiki that says the following: "Related articles: A Pirate's Tail Quest, Rascacoon."
Rita's Letter (Book) - Tibia Wiki
Updates/12.60 - Tibia Wiki
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