I was thinking it would take a while to look back, but the new "upvoted submissions" tool is more useful than I thought. The project was Quilt[0] and here[1] is the comments on it. The other project I saw referenced in the comments was Pachyderm[2]. It looks like Dat indeed was referenced in the comments, and the main difference is Dat is distributed while Quilt is centralized (like github)...and Pachyderm is more like git.

[0] https://quiltdata.com/

[1] https://news.ycombinator.com/item?id=14771406

[2] http://www.pachyderm.io/

EDIT: Annnd...looking up, I see others have already referenced quilt in other comments here.

The other one I know of is datahub [1], which used to be frictionless data. It is from the same group that built CKAN.

[1] https://datahub.io/