Note the extra indentation on the "exif:FNumber" element and no indentation on the angle bracket that closes the "rdf:Description rdf:about" group. This pull request creates an XML that looks like this:
Beautiful--that's exactly what we wanted, right? Made the changes but also made a mess with my commits. It was a small change so I did it on the same branch like a1ex told me to do on pull request #798
In any case, this looks perfect and verified working in Adobe Camera Raw.