Sources told The Intercept that the letter was relayed by an individual affiliated with Stanford University. Some sources told the publication that it was about an incident involving Kavanaugh and a woman while they were in high school.
Attorney Debra Katz is representing the woman who is the subject of the letter, according to The Intercept. She declined to confirm to BuzzFeed News that she is representing the woman, and did not comment further
https://theintercept.com/2018/09/12/brett-kavanaugh-confirmation-dianne-feinstein/