As of DBDOC 11.6, bookmarks can be defined and built into the DBDOC project file as part of the build process. See Creating System Home Page, Text Annotations, Live Loop Annotations, and Bookmarks.
System bookmarks can only be edited or deleted by a system user. This is to prevent a single user from changing or removing a bookmark that is intended to be shared and used by other users accessing the project. If you do not wish to see system bookmarks, you can uncheck the box for "Show System Bookmarks in Menu" in the bookmarks manager.