SWC is a library that offers an API for (tiling) window managers that is lightweight at under 6,000 lines of code and is also light on dependencies. SWC isn't feature-complete but sounds like a nice starter project for those wishing to dive into the Wayland world.
What makes SWC interesting from a technical perspective is that it doesn't depend upon OpenGL or EGL for compositing but has its own basic drawing library called WLD. Among the missing features from SWC is DPMS monitor signaling, useful multi-monitor support, clipboard integration, and other items.
For those wishing to check out this Wayland SWC project developed by Michael Forney check out his project announcement or GitHub repository. Embedded below is a video showing off SWC.