So I'm sure someone noticed this since June 30, 2017 when the Master Trials DLC first launched for Zelda: Breath of the Wild, but this is the first many are hearing of it.
As discovered by Kamuilyn on Reddit, the poses that the monks are making in the room of the Master Sword are actually references to the seven sages of Ocarina of Time. As a refresher, the Master add-on contains several facets, one of which is the Trial of the Sword, also referred to as the Sword Monk's Shrine.
If you make it all the way to the end you'll come across the aforementioned monks, who are posed exactly like the sages from the Nintendo 64 classic. I just made the comment a few weeks ago that people are still discovering some amazing stuff in Breath of the Wild over a year later, and I really doubt this is the last time I'll be writing about this timeless game.
via destructoid https://www.destructoid.com/it-turns-out-there-s-a-pretty-amazing-ocarina-of-time-easter-egg-tucked-in-zelda-breath-of-the-wild-499024.phtml