There are a dozen abstract roles in ARIA: https://w3c.github.io/aria/#abstract_roles

At the above overview link, it clearly states that:

Abstract roles are used for the ontology. Authors MUST NOT use abstract roles in content.

However, in each abstract role definition, it's not quite as clear that authors aren't allowed to use these roles, and some authors do try to use some of the roles, like input, range, section, select, because they "seem like real roles". :)

There is a green note box in each abstract role definition that states, for example in composite:

composite is an abstract role used for the ontology.

This needs to also say (e.g. for composite):

Authors MUST NOT use composite role in content.

However, since normative statements like "MUST NOT" are not allowed in Note boxes, we also need to remove the "Note box" styling (class="note").

Also, consider moving this text nearer to the beginning of the definition, perhaps right after the first sentence. (In some abstract roles there's only one sentence, so the text wouldn't need to move).

Thanks for taking this on, @jorycunningham!