In the rare event where same torrent is downloaded with different title and url this plugin will step in and see its unique fingerprint (info_hash) and reject it.
This plugin is Builtin and needs no configuration, however you can override some default behavior by configuring it explicitly.
To only consider previously grabbed torrents within the current task you can configure like this:
seen_info_hash: local
To turn off this plugin on a particular task, you can either use the disable plugin, or configure it like this:
seen_info_hash: no