A PDF carries more than its pages. This tool reads it and tells you what it found: what is active, what identifies you, and how many earlier versions are still sleeping inside.
What it does not do: An inspection does not tell you a document is safe, it tells you what we could read in its bytes. A PDF whose objects are compressed can hide active content from this scan, and the report says so when that is the case. Nothing from a document is ever executed here, and everything produced is rebuilt page by page.
Nothing is uploaded. Cut your network connection once this page has loaded: the tool keeps working. How to check it yourself.