Re: Is it possible to add additional metadata to a pdf?
It isn't supported out-of-the-box, but would certainly be possible. For the
automatic PDF generation, Orbeon Forms uses Flying Saucer. I'm not sure if
it supports adding key/values to the Document Information Dictionary (see
1st link below). If not, we could use iText to add this information to the
PDF once produced by Flying Saucer (see 2nd link below, in particular the
example at the end of the answer).