They don’t list pdfinfo there, but it is a part of their open source tool set. It’s a companion tool to xpdf and pdftohtml.
I like to use the creation date (or last modification date) of (external) documents as the leading part of their file names on my computers.
I use pdfinfo for extracting CreationDate and ModDate from PDF files:
$ pdfinfo … $ pdfinfo -rawdates …
Of course I like the raw dates better for this purpose than the “human readable” ones.
BTW: The raw date look a little like they are UCT or GMT, but they apparently aren’t.
Update 2016-02-23: Quite a while ago I created scripts (pdf-suggest-rename-as_vouchers.sh and pdf-suggest-rename-versioned.sh) that maked use of the dates extracted by this utility and I have been using them a lot.