Why do I not have matte nodes?

Why do I not have matte nodes? I have all the other nodes. I’m very confused.

Edit: Ok, so i have matte nodes in the compositor, just not in the shader editor.

I just watched this video where there was essentially a green screen node setup, all in the shader editor.

If you can essentially create a node setup to key something out in the shader editor, why can’t you just use the matte nodes in the shader editor? Or, why is it that you can’t use any matte nodes at all in the shader editor, but you can in the compositor?