Take a look at the REMNux reverse engineering page for PDF documents (https://docs.remnux.org/discover-the-tools/analyze+documents/pdf https://docs.remnux.org/d

Take a look at the REMNux reverse engineering page for PDF documents (https://docs.remnux.org/discover-the-tools/analyze+documents/pdf https://docs.remnux.org/discover-the-tools/analyze+documents...). Lots of tools here for looking at malicious PDFs that can be used to inspect/understand even non-malicious documents.