Clarify the copyright of ACL Anthology metadata

In February 2019, I was in contact with ACL Anthology people (mostly @mjpost) about Wikidata integration. This was also a discussion in a Scholia issue https://github.com/fnielsen/scholia/issues/227

I now see the fine development of the ACL Anthology Web site with machine-readable data in MODS XML and I was wondering whether we are allowed to copy the metadata from ACL Anthology into Wikidata. Wikidata is CC0 and the ACL Anthology states CC BY or CC BY-NC-SA for the "materials". It is unclear whether author, title, year of publication and similar metadata are under that license or it is only the papers themselves that are under the Creative Commons license and that it that the metadata can be freely copied to Wikidata.

It would be nice if the FAQ could clarify what precisely what is meant by "materials" and their copyright.

Currently, Wikidata has fairly limited metadata from ACL. The data has mostly been setup manually, see, e.g., https://tools.wmflabs.org/scholia/publisher/Q4346375