Why the “Sune” algorithm works - permutung the edges [DE]

In most tutorials on the Rubik's Cube, you are simply presented with algorithms without an explanation of why they work. In this series, I will look at and derive the algorithms from the beginner's method for the Rubik's Cube. So it's about really understanding these algorithms.
In this video, we'll look at how to actually come up with the “Sune” algorithm that is used to permute the edges (in the last layer).