Mesa is a long-running project that started life as an open-source driver, bringing the OpenGL graphics API to a host of different platforms. Today, developers from AMD, Google, Intel, and others all take part. One of the most well-known Mesa drivers is RADV: A Vulkan-based driver specifically for AMD's GPUs running on a Linux operating system. A recent update to them, created by Valve's developers, has added a neat little performance boost for any device using them.
Naturally, what's been done is all very complicated, but it comes down to this: Drivers for graphics cards contain a program called a compiler that converts shader programs that a game or application has issued into a binary format that the GPU can then run.
