If you are creating a commercial PC game using Godot there is a good chance you are going to want to publish on Steam. If that is a case if your game requires any network services such as achievements, a leaderboard or DLC you are probably tempted to use Steam’s own Steamworks suite of APIs. In that case you most likely want to know about GodotSteam an open source implementation of the SteamWorks API for Godot 2/3, providing convenient GDScript interfaces for the vast majority of the Steamworks features.
GodotSteam is an open source project hosted on GitHub that is implemented using the Godot module system. The source code is under the flexible and permissive MIT license. There is a GDNative branch available although sadly it appears to have been abandoned. Being a module means you will have to download and build your own version of Godot, a process I describe in this video. If the world of Godot, modules and GDNative are all new to you, don’t worry, we have an overview available here.