My bet would be the drawers of one publisher. The number is far too low to be even "two publishers." Anything that a publisher is legally entitled to store in t

My bet would be the drawers of one publisher. The number is far too low to be even "two publishers." Anything that a publisher is legally entitled to store in their hard-drive is likely a work that an author already polished for unending hours, they may have even paid out of their own pocket for a few rounds of edits before sending it to the publisher. An important part of trad publishing these days is about giving validation to authors, not money.