That bookmark manager sounds like an interesting experiment, so if you ever feel like uploading it why not.
What I’ve occasionally wanted to do is simply stick some tags to a bookmark, when neither the URL nor the title is descriptive enough to be easily retrievable through dmenu’s omni search. But so far I haven’t wanted it enough to figure out how to implement it, ideally with minimal code. Maybe as a hook if that ever becomes a thing, or by extending the “Page bookmarked” notification with an interactive element.