The plug-in changes the format of values in columns 'Seeds' and 'Peers' in the torrents list. By default these columns are shown as
get_peers_complete (get_peers_not_connected+get_peers_connected) get_peers_accounted (get_peers_not_connected+get_peers_connected)
For trackers which support scrape, is makes sense to show more details
get_peers_complete (t_get_scrape_complete) get_peers_accounted (t_get_scrape_incomplete)
I.e. the sum of seeds/peers by scrape of all torrent's trackers is shown in brackets. As shown below:
Another front-end for rTorrent wTorrent shows this information similarly. If you mostly use private trackers this plug-in is useless for you. Scrape is disabled on such trackers and you will have less information than without this plug-in - there always will be zero in brackets.