Even though the last sentence reference IBM platforms, we (large organization) are using those licenses for Windows and Unix development.
What is interesting is the "advanced building with dependency management, build impact analysis, deployment support (z/OS, IBM i, UNIX, and Linux) and advanced context aware search."
So yes, you can use those licenses outside of IBM platforms.
We also have simple "Developers" licenses, as presented in "Licensing in the Rational solution for Collaborative Lifecycle Management (CLM) 2012".