After I finished all endings and uninstalled the game, I found leftover file in the game folder:
- steamapps\common\The NOexistenceN of you AND me.

It didn't show up 2nd time after reinstalling and uninstalling(without playing), maybe the condition for it to show up is finishing one of the the endings... I don't know.
Just wanted to share a smol thing I found.

I know some steam games leave behind a few leftover files, but I didn't see stuff like this yet :)


Spoiler below:
She was there for us all along. ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀