It is in fact totally clear. There is a LICENSE file in the root of the repository. Adding a new subtree (directory) should not call into question whether or no

It is in fact totally clear. There is a LICENSE file in the root of the repository. Adding a new subtree (directory) should not call into question whether or not that tree is covered by the preexisting license. That's silly. If they wanted to change the license then there needs to be an actual change to the license.