[hollerith]

>The engine is also open source

I think you mean the source code is available (i.e., anyone can download it), which is different from its coming with an open-source license, which is what most people mean by "open source".

[pantalaimon]

No, what you mean is Free Software

[vetinari]

No, it's not Open Source either: http://opensource.org/osd

[nulltype]

I think microsoft calls this "Shared Source"

[SXX]

Actually no. Microsoft branded several licenses that way, but some of them are OSI-approved and FSF-approved (while not compatible with GPL).

[nulltype]

Then I guess we need a new name. The engine is "readable source"