Well, I have left it there. After un-zipping, it is a folder called "ExpatConverterOSX Folder", and inside it is a folder named "__MACOSX" with nothing in it, and an apparent executable called "ExpatConverterOSX", and when I click on that, I get a notice that says: "There is no default application to open the 'ExpatConverterOSX' ". So, uh, I asked awhile ago, "how do you install it?", but maybe that is not the right question. Maybe I should ask "What am I doing wrong?". Can you answer that?