ProDG (pronounced "prodigy"), also known as TMAPI, is the official tool used by PS3 developers to debug PS3 software. It can be used to view and modify values of variables on running programs on your console. It can be used for real time modding (RTM) as well as basic debugging. Note that in order to modify games, you must first convert their EBOOT to a debug EBOOT. ProDG is supported only on DEX firmwares, due to being an official Sony SDK tool.
ProDG also requires that you acquire a license to use it, and is registered to developers that make apps and games for PS3. We can't provide a download link for this reason.
HEN users cannot use this API. You need a console with DEX capabilities, and HEN cannot provide that.