Emacs core requires FSF copyright assignment. Most of the configurations in Spacemacs use third party extensions which don't have the assignment. But being no

Emacs core requires FSF copyright assignment. Most of the configurations in Spacemacs use third party extensions which don't have the assignment. But being non-core is not really a barrier to installation in my opinion. In many ways it is a plus, allowing for out-of-cycle releases and to experiment / break compatibility at their own pace.