Trying to find the name of this plugin, please help.

I was using a contributor wordpress account for another website, and I found a plugin that let you add your own “box” at the bottom of your articles especially to source the links you got content from. Here’s a screenshot of it: https://i.imgur.com/YUnFhAH.jpg

I don’t have any way of checking the plugin name, so i need help identifying it, thanks