Valve has announced plans to open source 'GameNetworkingSockets' for developers, which is a basic transport layer for games.
This is notable, as Steam is not required in order to help developers with networking.
The GitHub page states "the intention is that on PC you can use the Steamworks version, and on other platforms, you can use this version," which implies that it could help specifically for Linux developers who need multiplayer functionality outside of Steam.
"We're still in the process of taking the code from the SteamNetworkingSockets library and making it ready to be open-sourced," writes Valve software developer Fletcher Dunn.
Interested developers can check out the GitHub page here, although the repository is still empty for now.