Being a bit of a webmaster, I wondered if these files, of type .xmp, were by any chance like XML files which meant that they could be opened with a text editor. Then, indeed, I successfully opened one up in NotePad. The content was all there but hard to read, being just one long line. However if you open it up in a HTML editor, all is revealed in neat lines complete with line numbers.
There you see EXIF data for your shot and all the ACR adjustments made to your work of art - including adjustments that you may not even have in your current version of ACR.
A real programmer could then write something that lists all the pictures taken with a "D50" AND a camera profile of "red sunlight" AND an aperture of "28/10" . . you know, that kind of SQL stuff. That is, if they were so inclined and bored with taking the oft-mentioned "real photographs"