Epic Games have released Unreal Engine 4.21 and it includes some interesting stuff on the Linux side of things.
From now, Unreal Engine will default to using the Vulkan API on Linux and fallback to OpenGL when that can't be used. This is going to be good for the future of Linux games, since it should help developers get better performance.
On top of that, it features a new media player for Linux with the bundled WebMMedia plugin which includes support for WebM VPX8/9 videos. To further improve Linux support, they now have a proper crash reporter interface so that they can "continue to improve support for Linux platforms".
That's just the improvements for Linux, there's absolutely tons more included in this release including Android and iOS optimizations as a result of Epic's work on Fornite.
It's also really nice to see Epic thank contributors, noting 121 improvements where submitted by the community to their GitHub. Although you can only access it with an Unreal Engine account.
More info on the official announcement.
Who knows, maybe now that Vulkan is in better shape in Unreal Engine, Epic Games might eventually bring Fortnite to Linux. I can dream right?