NekoWM is a simple compositor and tiling window manager written on the top of the GFXprim proxy backend.
A gfxprim backend is an abstraction for a screen or a (e-ink or LCD) display to render to and also for input devices e.g. keyboard, mouse, touchscreen, etc. There are different backends implemented in GFXprim ranging from X11 and Wayland, where applications run inside of a window, to a Linux DRM or a Framebuffer together with linux input layer where application runs on a whole display, all the way down to a small SPI e-ink or LCD displays connected to a small embedded Linux computer.
A proxy backend sits between applications and another backend (e.g. Linux DRM) and is multiplexing access to the screen and input devices. GFXprim proxy backend consists of a simple protocol for events and a SHM buffer for an application to render to. NekoWM uses proxy backend client library build on the top of the simple protocol to talk to the applications so that it can switch between which of them are shown on the screen and which receives input events.
See autogenerated source code documentation at https://gfxprim.github.io/nekowm/files.html