I want to cite the Ethereum Project's white paper. It was the document that announced the project and outlined its philosophies, properties, etc. However, in 2014 they moved the paper to GitHub and treat it as a living document. For example, although the paper was initially released in 2013, as of today it has 84 revisions on GitHub with the most recent being two hours ago. They do not make a PDF available that I have found, nor have I been able to locate a DOI.
I'm going to assume that I would need to cite a specific version of the document, but I'm not sure if there is a preferred way to do that.
Note this question is similar to, but distinct from, this question which addresses how to cite an entire repository that one owns. I'm asking how to cite a specific document within a repository owned by someone else.