Such are referred to as leaked documents. Not open source.
But, they are sources, you can compile them and build binaries.
Just because something is IN the Public Domain does not make it Open Source.
In my country, we do not have the concept of "Public Domain", and I very much doubt that the sources we speak of qualifies as Public Domain anyways.
Open source has been voluntarily forwarded and made available to the end user for examination. There was no such voluntary disclosure.
"Open source" has no strict definition, you prefer to look at it as defined by OSI, but they do not own the term, it has been around for much longer. What I have been saying is that when sources are so easily available, they are for all _practical purposes_ open sources - nobody knows who have them, who have seen them, who have used them, and what for, unless they just admit it. Some do so openly, and it has had zero consequences for them so far.