I'm not sure I understand your question completely - so if this does not answer it - please provide a few more details about what you want to download from where...
Dangerous content is a What-Object in the default ruleset - you can check what it contains in the GUI (->Mail Filter->What Objects->Dangerous Content)
else - `pmgdb dump` output should contain this as well
If you want to keep mails that match this what-object create a rule with higher priority that puts these mails into attachment quarantine
I hope this helps!