The 404 Error page is a page that we bloggers hope no-one ever gets to see. When needed we do have to make sure that the page is useful to the user who arrived there. This page comes into play when there is an error on the blogger’s side or on the user’s side. We could have a broken link on our site or the user could have mis-spelled something when navigating to a particular page.
Those widget areas in the footer are so helpful in many WordPress Theme layouts. I use the term ‘multi widgets’ for lack of another term. By multi widgets I mean the user adds one, two or three (could be more) widgets in a particular widget area and then the theme displays the added widgets spread evenly across the width of the page. A few images will put this into perspective.
If your WordPress theme originates from Underscores and you have not changed the default code in the footer there is a good chance that the Theme Check plugin will show that there is a possible hard-coded link in the code. This bit of information does not mean that there is anything wrong with your theme but for a user or prospective user of your theme, this bit of information could be problematic.