Just a guess here, but they may have requested they be allowed to keep the names of the note holders confidential along with any financial information ABOUT the note holders.
"here are nine exemptions available under FOIA, but issuers generally rely on the exemption for "trade secrets and commercial or financial information obtained from a person and privileged or confidential," under Section (b)(4) of FOIA, commonly referred to as the "(b)(4) exemption," when seeking confidential treatment in connection with the comment letter process."