The charts are NQ SEP Futures and the NYFANG Index, not the associated NYFANG futures contract. I think the index is a better tracking point as the futures don't trade with a lot of liquidity.
As stated by others NYFANG is broader than the five "Capital Letters" that make up the FAANG acronym.
It is made up of 10 stocks. You can learn more about the composition of the NYFANG here.
https://www.theice.com/fangplus
This tracking index is relatively new and might be worth following to see whether it provides any early clues for general market direction.