ZiggIRat is intended to provide a usable backend for LLVM IR, QBE, and potentially others.
The easy answer is that it isn't. The only functionality currently in place is the lexing of LLVM 9 IR. Actual processing and code generation has not been implemented yet (at least, not to a point where I could honestly suggest looking at it).
Maybe, maybe not. This isn't really a priority right now, though I do plan on looking at LIMN codegen again soon.
Ziggirat is a reflection both of what this project is and its design goals. Ziggirat is a LLVM IR backend written in Zig. Ziggurats were ancient religious temples, and Ziggirat is meant to be a sort of temple to traditional software practices.