The announcement of native support was made by James Stone, Unity's Technical Director for Platform Products, during the GDC conference.
“I know you’ll say: ‘But I’m already releasing games on Steam.’ That’s true. Thousands of Unity game developers have succeeded on Steam. However, until the launch of the Platform Toolkit, we never officially supported Steam. Historically, developers had to integrate Steamworks themselves, as well as publish and support their games on this platform,” Stone explained.
In addition, Unity now natively supports not only Steam itself but also devices based on SteamOS. According to Stone, the official solution can now be tested on the Steam Deck, and it will later be available on the upcoming Steam Machine mini-PC.
Stone stated that the company plans to regularly update Unity's runtime environment for Linux and improve its performance so that developers no longer need to use Proton—a compatibility layer that allows Windows games to run on the Steam Deck.
Stone also mentioned that Unity has achieved good results with Fortnite integration but cannot share details yet. Recall that the possibility of publishing games created on Unity in Fortnite became known at the end of last year when the competing companies Unity and Epic Games unexpectedly announced a partnership.