Actually the matter grown from SE using. It's quite bothering to: right click on rss link, choose "copy", then swich to tunderbird, right click on rss folder, choose "subscribe", push "Add", insert, ok. I'd prefer to: right click on rss link and choose the rss folder. The second motive for the question is that I'd like to look at implementation of interprocess manipulation of thunderbird. May be there is not exactly but something similar exist.