asking for a close friend
I have two steam accounts, and I was not able to see anything related to a game marked private from my second account except when family sharing was enabled between the accounts. With family sharing on I could see all private games from my primary account on my secondary (including games which were not installed on the local system).
If you have family sharing on, hold off. Otherwise as far as I know it works as intended.
It would probably be better if you said the game that you wanted to do this with.
and
Private is subjective. Do you mean as solo play or with friends. Most games have options to cover both instances.
deleted by creator
OP is not referring to private lobbies in a game, they are referring to marking a game private on Steam itself, a feature that hides from the world (and your friends) that you own or interact with a game.
https://help.steampowered.com/en/faqs/view/1150-C06F-4D62-4966
They’re basically asking if anyone who uses the feature has had the info leaked by Steam.
For when you don’t want your friends to know when you’re playing hentai games.