This is really confusing.

ARG8888 and it says Pixel depth: 32-bit Color

ARG2101010 and it says Pixel depth: 30-bit Color

I'm waiting for the first real 32-bit colour monitor, the one that becomes transparent when alpha is set to zero.

So you'd actually see through the monitor to the internals our out the other side? That would be interesting :)

I wonder why it's not ARG10101010 for 10-bit RGB + Alpha

Surely it's not actually 2 bit Alpha in ARG2101010

The alpha part of the framebuffer isn't actually used because monitors don't support an alpha channel, it's just convenient to pad everything out to 32 bits anyway.