Is nothing like the original MBFC app that used to be really useful. All this one did was slow down Firefox, and cause it to crash. I know this because Firefox was telling me so with a unclickable blinking annoying "MBFC is slowing down Firefox".
So it's gone.

The add-on reports "FN" (fake news) for websites that the MBFC website report as "mixed". It also reports "FN" on websites that aren't even listed on the MBFC website. It therefore CANNOT be pulling its information from the MBFC website; it's getting its data from somewhere else, and you can't trust whatever that source is, because it does not match the MBFC website.

I wish this addon would not collapse items on social media feeds. For instance, CNN shares on Facebook are collapsed, and regardless of whether I expand or collapse the item again, I cannot see who liked/reacted to the post, until I disable the addon in Firefox settings. So it's potentially two separate issues that I don't like with this addon. You can alert users to media outlets that don't meet certain criteria without collapsing anything, that's going overboard. And regardless, the addon should not interfere with the display of your likes, et al, on social media.

11 July 2022 update: I had a notification today on Facebook that someone had commented on ~my~ post (an article from the Guardian). I noticed when I posted the article that this Firefox addon had collapsed it but just ignored that. But when I received the comment notification today, and clicked on it, it just seemed to take me to a blank page. So I tried "hacking" the URL to remove parameters one by one, then I saw it was the collapsed Guardian post that received the comment, but I still saw no comment. Finally, I disabled this addon, and then I could see and read the comment. At the very least, affecting social posts should be a separate behavior from rating an actual website I am visiting, and an optional behavior that can be turned off (especially until it actually does not interfere with anything, and things like the "show anyway?" link can be see in, e.g., Facebook's dark mode (I keep dark mode turned off when I enable this addon, but I think I am going to disable the addon permanently instead, because I use dark mode everywhere.