Transmission
There aren't many levels leftovers in the files for the transmission, but it shows some very interesting older versions of some we got.
LVL_6_070_FindingMonsterSix_02 is a blockout version of the rooms we find monster six in. The second image shows it much more similar to the room at the hunter's basement.
LVL_6_070_FindingMonsterSix_03_Warped is a blockout version of the room we find monster six in too, except this one seems to be a little bit older, as it resembles the bedroom we would find six in the very first stages of development.
LVL_6_140_CollapsingRunExit is an older version of the collapsing sequence of the ending for the transmission. The first one shows it less collapsed, while the second one shows it completely collapsed with a bunch of flesh everywhere. In this version, six doesn't drop you. She just ignores you.
There is a lot of mention of a "SafeSpace/CozySpace" in the transmission levels paths. Not sure if this is meant to be about the room we find monster six in or something else.
Originally we would find the thin man's office in the transmission.