alt Hacker News> Cancel doesn't navigate. In fact, neither of them do.
This is correct. The point of the proposal is that you should be able to implement this pattern with just navigations, and that implementing it differently doesn't change the user semantics.
> If you've taken the twenty lines of css to make a button look like anything other than the default browser styles, you can add the two lines of progressive enhancement JavaScript to handle space.
One important stakeholder for the proposal is governments and other websites that care about building accessible web experiences that work without JavaScript enabled. There are also many differences in the behaviors that can't be rectified with JavaScript (some examples are in the original article as well as the linked proposal).
While editing one GitHub comment I may be writing another. If you must, implement it as a link, but all else equal I’d prefer keeping the other state alive when canceling one comment-edit. Doing both is cool too, but people don’t typically want to implement a feature twice.