Lunchtime.
I have not exactly solved the problem, but I can say that posting a bookmark from Omnibear, using the Firefox extension, does work. That is, the description is received and used by Known.
@AgroBioDiverse So true. Feeds make it so much easier for people to keep up with websites of interest. Case in point: one of my favourite backgarden plant breeders sprang back to life after a gap of 8 years, and I was immediately informed. https://daughterofthesoil.blogspot.com/
So glad to see this site spring back to life, and this post is a great example of how anecdote can illuminate data.