My assumption is that he got rasa_nlu from pypi (we always encourage downloading from pypi, not github). And @samrudh you’re half right – installing rasa gets you both core and nlu functionality, under rasa/core and rasa/nlu inside rasa, but not the rasa_core and rasa_nlu packages themselves. These still exist, but are not part of the latest, rasa 1.0 and later.