What is the idea of White playing 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. c4 ? Does he intend to get some good version of the main lines, while avoiding certain sidelines? It seems in fashion now with games like this one, but I am not sure I grasp the full concept - Ian Nepomniachtchi vs Sanan Sjugirov, 2016