More on what is stored at IRON MOUNTAIN PA -
Reference from Penn State:
www.psu.edu...
In the same room, there are more than 400 boxes of memorabilia that mourners left at the crash site of Flight 93, which went down in Somerset County
on Sept. 11, 2001. The boxes are filled with items, including gloves, sports equipment and toys, all left by people in the past four years. A
papier-mache U.S. flag created by a middle school in Little Rock, Ark., sits in a corner, wrapped in plastic to prevent fading. In the middle of two
large shelves filled with boxes lies a bench with engravings from visitors to the crash site. Messages are inscribed all over the bench, paying
respect to those lost in the tragedy.

Here is reference from National Park Service which maintains crash site
64.233.169.104...:dFyTrKILY2wJ:www.nps.gov/flni/parkmgmt/upload/fiscalyear06.pdf+iron+mountain+flight+93&hl=en&ct=clnk
&cd=12&gl=us&ie=UTF-8
XI. Tribute and Object Collection Collecting, sorting, cleaning, maintaining, cataloguing, accessioning, and storing the tributes left at the
temporary memorial continues to be a major focus for our Curator. The tributes collected to date number well over 25,000. The following was
accomplished this past year with the assistance of two part-time staff hired by the Families of Flight 93 in cooperation with the NPS, and by SCA
interns: • 56 new groups of objects accessioned • 56 new groups of objects accessioned • 2,150 objects cataloged • 3,877 records added to the
cataloging database • 54 boxes of objects sent to remote long-term storage at Iron Mountain

So can see what was sent to IRON MOUNTAIN were tributes and
memorabilia left at crash site - Not some SOOPER SEEKRIT stuff
trying to hide from you.
Research - its a wonderful thing, use it!
(all this took 10 min using GOOGLE!)