Such cynicism in the video description update, and comments disabled. Sad to see that happen to such awesome hobby of deep zooming fractals :( About the code:

Such cynicism in the video description update, and comments disabled. Sad to see that happen to such awesome hobby of deep zooming fractals :( About the code: I don't know about the specific techniques they use, but in general some type of arbitrary precision math is likely used, where you represent numbers with a variable amount of bytes with more bits for higher precision, and using optimized multiplication algorithms that use less than O(n^2) time with n the amount of bits of the numbers