Works, but under another name Puntuado con 2 de 5 estrellas
This extension does its quite limited job. The ads on Facebook Newsfeed went away, as did the "suggested" stuff.
That isn't a fair trade for the fact that I can't uninstall this extension (if I were so inclined) because it does not appear in the list of extensions in FF add-on manager (which may have been Phoenix's point below). This no-start add-on says it's installed, and there are behaviours that indicate that it's installed, but I can't find it after it's installed. That's bad (malware-like) behaviour.
This should be a no-star rating (if that were allowed), until this behaviour is corrected.
[So, if I wanted to do so, how do I get rid of it (or disable it)? (I can't believe this got by the Mozilla review people.)]
UPDATE: I've found the entry is the Add-ons extensions list, under the name No Facebook Page Recommend, not the name listed here, "QCLean:Remove Facebook Ads,Suggested Pages&Posts" (or some version thereof), which is still bad behaviour.
I've revised my star-rating accordingly.
Sorry about that the name of this add-on. "No Facebook Page Recommend" is first name of this add-on. Then, I update this add-on (add remove ads) but forgot to update the name in source code of this add-on. Thanks for your reminding. I just fix it and wait for review.
[Update: now you can download the new version :)) ]