Description from extension meta
Removes any HTML elements with 'fixed' or 'static' positioning from the page
Image from store
Description from store
Lets you click a toolbar button to remove annoying 'floating' HTML elements (sign-up forms, feedback buttons, cookie notifications, etc.) from the current page.
It's not permanent - to get them back then just reload the page (press F5, or Command+R, or Ctrl+R, depending on your browser).