It's me again, coming back from "debugland˝.
So ... as I expected (and, since you re-wrote almost the whole recipe) there's
no more red lines with 'ebook-convert' and it -- at last ! -- yielded the articles.
BUT ... it remains one « small » problem as, actually, it yields only 10 or 15 lines of the articles and these ended by a sentence like : « Please, feel free to subscribe to Mediapart in order to read blahhh... »
So, I wondered : « had it a link with the "logging snippet"? », « is it useful? », etc...?
At this stage, I think the best thing to do could be ... opening a new thread?
I go opening "Subscribing in 'Mediapart' [new] recipe don't work" ...