At the Institute for Software we have been developing plug-ins for Eclipse CDT for almost a decade. Some of this work has been contributed back to Eclipse (e.g. the majority of refactorings and the underlying infrastructure for writing refactorings), others like Linticator are available commercially, but the majority is open source (e.g. Metriculator) or free to use (e.g. CUTE).
Over time, as more and more plug-ins were created, it became tedious to discover and install them one by one. So we decided to bundle them all into one single download, including the latest release of Eclipse CDT.