For the return values, I followed this rule: if the fuction returns true on success, it should return false, error on error; for every other case it should return nil, error on error.
Also, who doesn't want to edit code in 3D ? The line depth depends on the indentation level.
Accessible with require("ctr.fs.lzlib"). I just added the file "lzlib.c" in the source/ directory, because it's much simpler to build.
https://github.com/LuaDist/lzlib for details and documentation.