Complex sentence: It is mentioned in "An Attempt to Escape" that there is a human resident (or spy) on Tagora whose name is presumably Benny Durov (Бенни Дуров) and he is a progressor working under cover to study Tagorian technology.
Split into simpler sentences: It is mentioned in "An Attempt to Escape" that there is a human resident (or spy) on Tagora. His name is presumably Benny Durov (Бенни Дуров) and he is a progressor working under cover on the planet to study Tagorian technology.