Cyphia provides VirgoViewer for PDF

Cyphia Software Development provides VirgoViewer, an Explorer-style lookup utility to browse the internal structures of PDF files, including the internal structures of embedded resources such as fonts.

Acrobat and other viewer applications shows the page graphics on screen, but VirgoViewer opens the PDF document as if it were a ZIP package with internal “folders” and “files”. Of course these are virtual organizations that are conceptually similar to the disk file system structure, yet it comes handy when you can refer to a certain item with a distinct virtual path, and when you can directly operate on the item in a similar fashion, be it a page, an image, or a font.

As a typical lookup tool would do, you can examine the bytes, text, properties, etc. of the data objects inside the PDF, and even invoke operations on the objects directly. Please visit the website http://www.cyphia.com for more details.