There should be a feature to enable user to easily import/export bookmarks in a file.
Also another useful feature is needed to export bookmarks to chm file.
These features will boost the comprehension.
This is already possible from a very early release (Zekr 0.5.0). You can export bookmark sets into both HTML and XML format (XML is also importable, but HTML is only for seeing bookmarks with a web browser),
Try: Bookmarks > Manage Bookmark Sets.
Please note that "Manage Bookmark Sets" have a bug with latest 0.7.5beta4 which prevents import/export. You should either use another version (older one), or wait for the next release.