The logic in ros2/ci has two options to use Connext:
- either install the Debian package available (which implies accepting the embedded license) or install Connext on macOS / Windows machines
- or build Connext from source (that is what the
osrf/rticonnextdds-src repo is for). Since this repo is private you would need to talk to RTI if you want access to their sources in a similar way.
Sticking to just the first option is probably fine for you.