@DoncoMarketing, it’s something I honestly haven’t gotten around to documenting yet, but was implemented based on a collection of feedback from users to be able to make contextual overrides to things like Headers and Footers more simple.
Before this release, if you needed two headers on your site (e.g. one globally and one for just your home page), you’d have to manage the assignments of those headers from within the headers themselves, which is fine, but in the case of just needing to output one unique header here or there, it is a bit of digging to find it.
Now, you can simply assign an override directly from the Layout Assignments here. “Default” would pull through your “global” header as it’s the primary assignment made for all contexts, but you could also simply use that dropdown to pull in any other Header you want directly on that page.
Same goes for generic page layouts or things like that. Maybe you want a default “fullwidth” layout assigned everywhere using the Layout Builder, but there are times you want a sidebar layout. Instead of having to go into the sidebar layout and assign it to a bunch of random contexts, you can just overwrite it on the page and add it there.
Hopefully that makes sense!