From the comments here I can infer that it has a schema and in turn I can extrapolate that this is as much "for humans" as many other config formats that are deterministically parseable.

A GUI is a config format for humans as it can you show what all of the configuration options are along with text that tells you what they do. A GUI can also ensure that there are no invalid settings that are discovered separately from the edit session (sure it may not do so, but it has the possibility unlike whatever random text editor the user opens the config in).