#renderer None... does exactly what it says on the tin., it doesn't load the Rendering Engine (be that OpenGL or Vulkan)
This is primarily for Applications that you don't need Graphics for, instead you just want them to run in the Terminal or such... say like a Dedicated Server Runtime.
Honestly I don't see this being a particularly useful Feature (given it's currently limited to Windows only) and AppGameKit Tier 1 doesn't exactly have great Console Features at present.
Hence why it says to use Swap instead of Sync... as Swap (unlike the name suggests) just updates the Core AppGameKit Logic., if the Renderer is running it will also perform a Backbuffer Flip but that's Conditional on a Completed "Render()" Call... if you never call Render() then the Buffer Doesn't get Flipped as the Data should remain the same; and I'd wager if it's blank then it's essentially calling a NULL Pointer.
It could be useful in Tier 2 Console Apps., but yeah... don't see many use cases for Tier 1.