Nowhere. But did I say this is a problem?
Answer this question:
Since we know that Christians, from the earliest times, treasured and venerated relics (We have Jesus’ shroud, much of the true cross, the bones of many of the apostles, etc.) why do we have not a particle of a bone from the body of Mary? Not only that, there is not a trace of anybody’s ever even CLAIMING to have had a tiniest relic from the body of Mary.
My own explanation for the complete absence of even a CLAIMED relic of Mary is that even all the would-be fraudsters knew that no such claim would be believed, because belief in the bodily assumption of Mary into heaven was always universal among Christians.
Do you have an alternative credible explanation for the complete absence of any claim of a relic from the body of Mary?
Arguing from LACK of evidence??