It's really clear to me. (And I did account for the subsequent README commits since your comment). But that's probably because I already know Web Components well. I'm in the market.

In the following line...

> Hyphen - A custom element base class for great developer ergonomics.

...I would recommend adding a link on "custom element" that points to a definition somewhere. This might make it easier for skimmers to parse the meaning of this opening line.