Because so many different video cards are made from a handful of chip designs, there is a group of people who like to see whether a lower-end SKU can be unlocked to behave like a higher-end one. In this case, kdtree on the ChipHell forums has apparently flashed the new AMD RX Vega 56 with the vBIOS from an AMD RX Vega 64. Personally, I would find that a little sketchy, given the difference in stream processor count, but they’re the one with the graphics card.
Turns out, it did something, but it did not magically create an RX Vega 64. The extra 512 shaders are probably disabled at the hardware level, such as with a laser. Your first reaction is probably “well, of course it is…” but, if you remember Polaris, users have software-modified 4GB cards into 8GB cards… so there is some precedence for “maybe AMD put more on the card than they said on the box”.
Oh right, so what did it do? It apparently gave the card a significant overclock. It’s hard to tell under the watermark, but the modified Vega 56 was just a percent or so away from the Vega 64 on 3DMark. I’m guessing a conventional overclock might do the same, but who knows.