magaudet and I are from IBM and are happy to answer any questions. tl;dr: IBM is breaking apart its JVM runtime technology to allow easy reuse and integration of its GC, JIT and Tooling into other languages. This has been proven with a JIT + GC + Diagnostics enabled version of Ruby (MRI) and Python (CPython)
Congrats on the public announce of your 'secret' project! When do you release the code publicly? It would be great to be able to hack on it again.
One of the key parts of this project is that we are using the code in production. Each piece is being used in our shipping releases like Java.
Open sourcing will happen. Doing it right is very important to us however, so we don't know when.