From the given information, I could imagine either of two things: (1) the license of the whole project has been changed to remove the NC clause, but some files have out of date licensing info in them; or (2) different parts of the project are under different licenses.
I do not have any direct administrative role, but this is probably a case of deprecated information in the older works.
The license is noted here as well: http://perseusdl.github.io/treebank_data/
Would it be possible to edit the README file to clarify the license?
The README file says the license is CC-BY-SA. However, there are files inside the project that have different licensing information. For example, at https://github.com/PerseusDL/treebank_data/tree/master/v1/greek it says it's CC-BY-NC-SA.
From the given information, I could imagine either of two things: (1) the license of the whole project has been changed to remove the NC clause, but some files have out of date licensing info in them; or (2) different parts of the project are under different licenses.
Thanks!