Is this the gold-standard for all-road and gravel 2x groups? 

Possibly. 

With the same proven hydraulic brakes and Shimano’s light action shifting technology as their Ultegra road parts, this GRX kit is optimized for going beyond just tarmac.  Designed around a 46/30 or 48/32 crankset (not included) and paired with an 11-34 cassette you’ll always have the gears needed to tackle the day’s adventure. 

Kit includes shifters, hydraulic disc brake calipers, front and rear derailleur, chain, and 11-34 cassette.