I thnk a tiny correction is required in the manual section on ebook formatting:
“One important thing to consider is that the title prefix and suffix entries will be printed
even if the Title is disabled for that row. This can prove very useful in some cases. It could
for example let you use casual titles in the binder, and standard generic numbered titles
in the final output. These are set specifically for each formatting rule established in the
structure table. This means a folder on level 1 could use Part <$R>, while a folder on level
2 could use Chapter <$n>, and folders of level three and higher would use the hierarchical
numbering provided by the ?? tag. Meanwhile text items could use something else
entirely, or nothing at all.”
There is a way in the Mac version of escaping token codes. You can type them in as <$n> instead of <$n>, which will result in the final output printing the literal token instead of substituting it for a numeral. This is how I can use Scrivener to write about tokens—but in this case the <$hn> token is malfunctioning, and printing “??” instead.