[kkowalczyk]

There's nothing to clarify.

Creative work (including source code) automatically falls under "all rights reserved" bucket unless the author specifically states other licensing terms.

In this case the author didn't so his work is still "all rights reserved" and no-one can use it.

You're confusing "source code available" with "open-source".

"Open source" is a shortcut for: "source code available and under open-source license".

What license is an open-source license? OSI has a detailed checklist: http://opensource.org/docs/osd

(nitpicker corner: to the extent a vague term as "open source" can be defined; people disagree as to what exactly it means).