Recently, a player with the nickname Old_Ambassador1702 shared a discovery with the Hollow Knight: Silksong community. He noticed a cutscene in the game files that he hadn't seen in the game:
I was browsing the old Silksong game files (Switch version, BEFORE the DLC announcement) and came across this hidden cutscene / scene transition (it was called Submersible_Travel.mp4). I didn't find it anywhere in the game itself — maybe it's for an add-on (although that would be strange, since the game files date back to BEFORE the DLC announcement), or it refers to content that I just didn't discover. I hope someone can explain (please, Team Cherry, EXPLAIN!).
Thanks to other members of the Hollow Knight: Silksong community, it was established that the file with the cutscene was created at the end of 2020 (2020:12:14 06:51:58 according to metadata).
Players speculate that the submarine cutscene may have been related to an underwater location that did not make it into the release version of the game.
In mid-December, Team Cherry announced the Sea of Sorrow add-on.