I find the wording ambiguous, but this:

> Eink mode is not a closed-file format reader but rather a form of responsive web design (RWD) integrated into the website itself.

suggests to me that it's a display mode you have to enable in the CSS design of the site, like "print" layout. I.e. this particular version is not software you can use on any site, it has to be baked into the site.

Yes it is, he has instructions here on how to enable it on your site: https://github.com/jack101311/Eink-Module

Now the quest is to make this something that the user instead enables on her device for all sites.