The latest version of PDF/A, a subset of PDF suitable for long-term archiving, is now available as ISO standard 19005-3:2012. According to the PDF/A Association Newsletter, “there is only one new feature with PDF/A-3, namely that any source format can be embedded in a PDF/A file.”
This strikes me as a really bad idea. The whole point of PDF/A is to restrict content to a known, self-contained set of options. The new version provides a back door that allows literally anything. The intent, according to the article, is to let archivists save documents in their original format as well as their PDF representation. Certainly saving the originals is a good archiving practice, but it should be done in an archival package, not in a PDF format designed for archiving.
Mission creep afflicts projects of all kinds, and this is a case in point.