Update "Skip links (Skip to main content): What is considered "Main Content"?"

[Jefferydo]

The answer is
"Usually, it's the h1 of the page. If there isn't any, it should be where the unique content of the page begins (in other words: after any repetitive menu items)."

It's worth mentioning the main element/landmark. It's a sensible target.

The "More Information" section is pretty confusing here:
"However, if there is unique content found before the maint content such as a "New on this page" section floating in the navigation menu itself for example, it must be communicated to assistive technologies. An aria-live may be used accordingly."

Skip navigation links are intended for sighted keyboard users, landmarks for screen reader users. So this answer is mixing the two. If the "New on this page" heading and content are in a landmark like nav they're accessible. Also, aria-live is for dynamic content so doesn't apply to this scenario.

Course page on Skip navigation links