Thanks, @lyonwj,
I did look at the documentation you referenced before I posted. But I noted that the defaultCaption was only shown against Nodes. In my dealings with tools over the decades, I've found that unless something is explicitly mentioned, "all bets may be off:. That's why I asked the "cognoscenti".
I asked related to my other topic Are nodes in "db.schema.visualization()" the same as model nodes?regarding the virtual nodes rendered on the db.schema.visualization function. When I asked this question, the schema relationships were blank (where we used defaultCaption), but we've since changed the styling, and the defaultCaption for the nodes also doesn't work there.
Paolo