Pin It од Ryan

Source code here: https://github.com/rysllvn/pin-it-extension

Allows you to pin elements to the page so that they stay in view.

A copy is made of selected elements that you can move around the page. These copies are easily deleted.

The styling or look of things on websites usually depends on the other elements around it. For this reason pinned elements will often look different than original versions.

Permissions: “Access your data for all websites”. This extension needs access to the page you are on in order to make copies and pin them to the page. See this article for more information: https://blog.mozilla.org/addons/2018/02/01/understanding-extension-permission-requests/