The CDT Debug Integration framework, CDI, has been removed. It has not been maintained for many years. Integrators must now use the Debug Services Framework, DSF, or program to the Eclipse Platform Debug APIs directly as TCF does.
After years of struggling with the CDT managed build system to integrate with external managed build systems such as qmake and cmake, a new build system has been constructed. It is much lighter weight and gives the integrator full control of the build process will maintaining core CDT features such as parsing and error reporting. As it matures, it might become functional enough to replace the existing managed build system, or at least support it as a layer above.
CDT no longer depends on RSE. Instead, the newer, more maintained org.eclipse.remote plugin is used for CDT remote debugging.