The link that you gave is my general reference, and it's the link that I usually give out. As for a definition, for me at least, a dualLived module is part of the core but can be downloaded and installed without the need to reinstall perl.

As for corelist, I wanted a script that, like corelist, would enable me to enter a module name and get back an answer about whether it was dualLived or not dualLived.