Hi, Paul
The ambiguity in my concern does not refer to the different versions of the MIT license, but it is about the different possible interpretations of that statement (still part of the expat license). Licenses like GPL/LGPL/BSD (I'm not pushing any of these, especially GPL/LGPL) has, as well, different licenses, but they are all clearer in their statements.
I *imagine* that making Lua as available as possible is on the author's desires, and ZLIB fits that better than MIT.
