Reach the "Minimum Viable Product" status as the Vulkan Portability implementation.
Khronos initiative announcement
Meta issue: #1354

Deliverables:

1. Low-level core library with minimal overhead
2. Supported API backends (for a few simple tests)
   - Vulkan
   - D3D12
   - Metal
   - GL (optional)
3. Consuming SPIRV shaders: #1374
4. Static+dynamic library as a direct replacement for libvulkan.so, building with vulkan.h, possibly with the required extension produced by the portability TSG.