XOOPS Cube project wrote a new core from a scratch and licensed the core under the modified BSD. By that, XC became able to link with many kinds of libraries. Also xoops.org may choose a change of the lisence, because they plan that XOOPS3 will contains JpGraph. JpGraph freeware edition is licensed under QPL. QPL conflicts to GPL, so GPL software can not link with QPL code like JpGraph. This is the reason why I think that XOOPS3's license will not GPL.
Now, XOOPS3 code that we can check on SVN is XoopsSphere and is lisenced under GPL. I hread that XOOPS3 is developed in Beijing, so another XOOPS3 may exist at Beijing and may be licensed under a new license different from GPL.
If XOOPS3 will change its license, I think that is better. GPL is not good for PHP freeware world, whether we agree FSF activity. GPL is great license, but, in PHP world, there are many libraries that take license conflicted to GPL. It's hard-to-use for developers who operate under PHP freeware activity.