Initializing the BookmarkManager with existing bookmarks form the template will allows to use asBookmarkRef() service on preexisting bookmarks with out M2Doc generating a dandling reference error in the generated document.
This might also be done with preexisting bookmark references since they can reference a bookmark that can be absent from the generated document. In this case it whould be nice to mark the reference as dandling in the generated document.
In fact this should be done while generating because a bookmark can be present in the template but absent of the generated document, or generated more than once.
Initializing the BookmarkManager with existing bookmarks form the template will allows to use asBookmarkRef() service on preexisting bookmarks with out M2Doc generating a dandling reference error in the generated document.
This might also be done with preexisting bookmark references since they can reference a bookmark that can be absent from the generated document. In this case it whould be nice to mark the reference as dandling in the generated document.