What is an AV grade switching power supply?

AV grade? Is that like a black one?

Yes I think an AV grade power supply is one that has better noise filtering on board. Like the IFI stuff as was mentioned.  Switch mode power supplies are notoriously noisy, so for AV use, I would think they put in various filters to quiet the noise so the music or video signal isn't affected.

@jumia

iFi audio IPower X Power Supply

Problem with linear power is that the circuit is always on and this creates noise. A switch power is fine if the filtering for high frequencies is done well and should not be a problem.

So linear power for switches it's not a good idea.

Let's go with mainly marketing BS. Bet they don't provide specs. Any quality PS has validated FCC class B test results. Most critical thing in audio is ensuring the switching frequency stays out of the audio frequencies and preferably high to make filtering easier.