http://bhqityoevbljuefl4m2khh3mw6ezcv7gg673qnyorka2o6loj3m6qead.onion/overview/limits-metadata-trail-much-possible
The source can only log into SecureDrop through the Tor Browser, which masks the source’s IP address to begin with, so there is no indication who the source is (unless they disclose it) and where they are sending information from. The Tor IP address, the computer, and the browser type that the source is using is not logged either.