Let <$levelN_title> go to empty string for oversized N

Request: Let <$levelN_title> go to empty string for oversized N.

Currently, that placeholder just keeps reiterating the current document’s title for N higher than the document’s own level. That is unexpected behavior and a misrepresentation, because it reports titles at levels where they are not. Nor can I think of a rationale for having it behave this way.

Details: Suppose we have a binder set up like this:

Draft [folder]
   Preliminaries [folder]
       Fall of the Empire [folder]
          Rise of the Xthians [a scene doc]
          Bad Broodings [a scene doc]

If the following is placed in the prefix for the first scene document

<$level1_title> / <$level2_title> / <$level3_title> / <$level4_title> / <$level5_title> / <$level6_title>

We will get on compile:

Draft / Preliminaries / Fall of the Empire / Rise of the Xthians / Rise of the Xthians / Rise of the Xthians

What we should see is:

Draft / Preliminaries / Fall of the Empire / Rise of the Xthians

I learned of this puzzling placeholder behavior while trying to help someone craft a way to have a breadcrumb appear on each of their compiled manuscript docs. Because of this odd placeholder behavior, making such a breadcumb prefix is not practically possible.

Best,
gr

P.S. The behavior may be entirely unintended. I did find in Forum history a report of a bug with this placeholder whereby it was giving the title of the document for every N. So, we may be seeing a vestige of that same bug.