Cryptomatte material passes – differences?

[pegot]

What is the differences between the following three Cryptomatte passes?

MatNodeName (using material node names)
MatNode (distinct material nodes)
MatNodePin (using material pin names)

They all seem to do the same thing. I thought by renaming the nodes to the same or giving them a label, I could group specific materials together. But that seems not to be the case. Renaming the nodes or giving them labels doesn’t seem to work.

How does one use these three passes and what different masks do they result in?

[linograndiotoy]

They all seems to do pretty much the same thing here.