While the free and open source game engine Godot Engine already has Linux support, for both exported games and the full editor, it's set to get even better in Godot 4.0.
In a blog post written by Camille Mohr-Daurat, they mentioned how they've been hired by the Godot team to work as a contractor on fixes and improvements for the Linux port of Godot. Camille Mohr-Daurat is an indie developer who actually uses Godot too at Nekomatata, where they created the unique ping-pong battler Punch Pong. So this is a real fun example of open source in action.
Godot 4.0 will be coming with a new windowing system, so that you can separate parts of the Godot Engine editor from the main window. A lot of their work is focused on ensuring that works great on Linux with X11, which seems like there's a lot of work involved, because there's places where X11 doesn't have APIs to handle things where it does on other platforms like Windows and macOS - with drag and drop between windows being one mentioned example they've had to solve directly.
Multi-windows could be seriously useful in a multi-monitor setup.
Another possible change they're discussing for after they fix up the current issues in on modernizing their implementation using XCB which is a replacement for Xlib. They also confirmed Wayland support is planned at some point, as a separate Display Server implementation.
Since Godot Engine is open source, it's always thoroughly interesting to be able to see what really goes on behind the scenes on these huge complicated projects. Their dedication to Linux and cross-platform in general is great too, showing others how it can be done.
Full blog post on it here.