Doesn't look like it. See the about page, I think that's a pretty good indicator he intends to host it (although might be open to selling a license).

Why isn't this project open-source?

Ultimately I'd like DevDocs to provide me with some income so I can keep improving it over the long-term. Until I figure out how to do that I've decided to keep the project closed-source. If you have comments or ideas about this I'd love to hear them.