Node group does not append.

Title say all. Here’s the story in pictures:

So… Can anyone help me? I have the feeling is something dumb, but it is really, really weird for it to not show up in the Datablocks. It does not appear at all.

Not sure if I’m seeing a node group in there, just a material setup. A node group would be a set of nodes that are grouped together by pressing CTRL-G so that when you tab out of the group editing mode it appears as a single node. What you have in the image here are framed nodes, which are just a way to help visually organize the nodes you have.

You’re using FRAMES rather than GROUPS.