They are for Kwinn's quest. Kwinn's quest is a sub quest needed for the Shackle of Tynnonium. If you recieve a faded white tome from the tomekeeper in kaesora, you will need to do Kwinn's quest, where you recieve a mechancal iksar tail. You then hand in the tail and tome into one of the guild masters in cabilis. I have done the quest so i would know.
Cathan Kazimyre, 52 disciple
Tarew Marr (Conquering Souls)