I dont really know, but a stud book normally registers breeding and more and more insist on dna proof.
Maybe this one is registered with them but with unknown or unproven breeding and just its micro chip to prove who it is?
I'm guessing really.......
Today is a gift.... thats why it is called "the present"
some stud books in the UK issue idetity papers to horses just so they have documents, becasue its law, but they wont have pedigree or anything like that on it, just a basic identiy document im guessing