I like the general idea... I think it's also a tall ask. When everyone asks for a different feature; there's too many features to implement.

HTML defines a <main> tag: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/ma...

> The <main> HTML element represents the dominant content of the <body> of a document. The main content area consists of content that is directly related to or expands upon the central topic of a document, or the central functionality of an application.

(And, yes, the above page has a "Skip to main content" link that shows when I hit tab.)

The thing is, <main> is how the page (via HTML) indicates what the main content is. The browser can have its own keystroke or semantics to find the main content.