Will it? The OpenGL xml spec is very important to those making bindings to other languages. If there aren’t plans currently then i suggest there be one 
Yes. It’s under src/spec/vk.xml in the Github Vulkan-Docs repository (may be relocated to another repo soon, though). The XML API registry is much more deeply intertwined with the Vulkan spec and reference pages than is the GL spec - it should be impossible to get inconsistent prototypes showing up in header, spec, and/or ref pages, for example, since they’re all derived from vk.xml - and includes considerable additional annotations, although the general structure is similar to the GL registry. We had to modify and extend the XML schema quite a bit to cover all the uses.