Export individual folder's bookmarks to file

Quick scenario. I am a writer. When I am working on a novel I do a lot of research on many subjects, consequently I have a lot of saved links to anything of interest. On completion of the novel I save a Master copy of print and ePub / Mobi versions together with all my research, drafts, edits etc. I would also like to save my bookmarks to a document to be included in that archive. I know in Firefox you can export all bookmarks to html document. But then, if I used that, I would have to edit it to only include the relevant bookmarks.

Is there a way I can export a single folder’s bookmarks to a html document? If not could some thought be given to include this as an improvement. I guess there would be a lot of people in my position who need to compartmentalize bookmarks and save them to an archive when the task is compete, rather than completely delete or retain them cluttering up the system.