So I found MDN's documentation on it (https://developer.mozilla.org/en-US/docs/Web/CSS/grid-templa...), but wasn't 100% certain on how the implementation works. Namely, how footer and foot were related.

At first I was thinking it was inferring first HTML element seen (head) relates to first area element written (also head), second HTML element seen (nav) and second distinct area element written (also nav), and third HTML element (footer) with third distinct area element written (foot). Then I see the pretty obvious grid-area within the CSS handling that linking and I must say, that's beautiful stuff.