I tried it on a big OCaml project (https://deepwiki.com/libguestfs/virt-v2v) and it seems correct albeit very superficial. It helps that the project is extensively documented and the code well commented, because my feeling is that it's digesting those code comments along with the documentation to produce the diagrams. It seems decent as a starting point to understanding the shape of the project if I'd never seen it before. This is the sort of thing you could do yourself but it might take an hour or more, so having it done for you is a productivity gain.