To me it looks like webclipper cloud stash or a web version of Copy as Markdown extension I found in the past. I think it could be quite useful for situations when there's no Joplin installed at the machine but you still want to clip an article.
Alternatively, the plugin is an implementation of rss fetching for Joplin. Maybe some of its codebase could be useful for building RSS related plugins
Thanks for sharing and recommending graphit0 (apparently I can't tag you as a new user) - if anyone tries it please do let me know your thoughts. I'm planning to blog about my workflow and how I'm using the plugin myself in the next couple of days.
I'm also aware of a current slightly annoying bug where some notes are being duplicated on first creation. I'll be looking into this in the next few days too.