As best as I can tell, it says the universe is holographic because all the information on the inside (a volume) is reflected by (or a reflection of) the information on the edge of the universe (a plane).
This makes it "holographic" because our 3-dimensional world is also expressed in 2-dimensions.
And the contention is that we can observe this because certain high-precision experiments might be picking up anomalies on the scale of a Planck length, whereas we shouldn't theoretically be able to detect anything so small. Therefore, what we're detecting must be an enlarged projection of what's actually there.
