It would seem that some studios have the ability to stream their projects via Steam.
As spotted by Sergey Galyonkin from SteamSpy on Twitter (below), there was a stream on the storefront page for The Red Strings Club. The broadcast is branded Devolver Digital, the game's publisher.
Since 2016, users have been able to let people view footage of what they are playing, but this is different, featuring the player in the footage a la a streaming site. There's even a Twitch-style rolling comments section featuring... usernames advertising CSGO skin sites...
We've reached out to Steam to see if they can tell us more about this feature. It's likely part of the on-going overhaul the platform's Curators system is undergoing. That changes were coming was announced in October 2017.
Looks exactly like Twitch, all right :) pic.twitter.com/limG2lW07A— Steam Spy (@Steam_Spy) January 24, 2018