I don't think I've seen this mentioned, likely because it's a simple, non-privacy extension.
Reading List. It works like bookmarks, but it is targeted at news articles and other things you want to read but don't necessarily want to "forever save".
It's made by Mozilla. The same devs that make Firefox. The articles you see below the search bar in the homepage when you first install Firefox are suggested by Pocket.
There are some awesome suggestions made by people here. Never heard before extensions that may come handy someday, that would otherwise require third party apps to do the same task.
Also, save the following two posts as well. I didn't notice similar posts were already created earlier.