Phusion Passenger — a.k.a. mod_rails — makes deployment of applications built on the revolutionary Ruby on Rails web framework a breeze. It follows the usual Ruby on Rails conventions, such as “Don’t-Repeat-Yourself”.

Note that the Ohloh source analysis is incorrect. The statistics for C++ and comment count are wrong because the Boost library is included. It is also not true that there's a single developer, because Passenger is commercially supported by Phusion.