MBFC accuses CNN of being "strongly left-wing" and the Economist as being "least biased". That should tell you everything you need to know about how flawed their "fact checking" is.

I really like the addon but it is not frequently updated. I would give it 5 stars if It was updated every season

No longer maintained.

https://github.com/JeffreyATW/mbfc_icon/issues/10 directs users to an extension for Chromium-based browsers, which can be added to Firefox 79.0 (with Chrome Store Foxified) however the extension is mostly unusable.

Update, 2020-12-06:

https://addons.mozilla.org/addon/media-bias-fact-check/

Also, for Firefox:
https://addons.mozilla.org/addon/fact-layer/

This is very useful to know who's interests & agenda are behind the news & what "inconvenient" info for the narrative the source could be omitting.

no color-coded icon. tried on multiple news sites: CNN Breitbart NYT . And what makes this extension "official"? sounds like fake news to me as it isn't worth a tinker's gob

Thanks Brooke

A very welcome work, but unfortunately the ratings themselves are sometimes biased. It's not very accurate to give BBC & Al Jazeera the same left-center rating. They usually have very different outlook about almost anything. I never felt BBC is anywhere near liberal. Also it shows a well known- highly anti-Minority, pro-BJP Indian news outlet Firstpost as "Left biased", same as famous libarel media Huffingtonpost!
Needs more research by neutral, highly educated source/person.
Probably has a memory leak.

REVIEW

I love this addon but it uses up to many resources when I have multiple tabs open.

I really like this extension, but it slows my browser down. I have a couple dozen installed and after disabling them all one by one, I determined that this was the one that was causing the performance problems. It seems to be slowing down page loads by a second or more. If it can be refactored to improve performance, I will consider using it again.

Nifty little add-on. Don't put all your weight in what some addon says; it's just supposed to alert you that what you're reading may not be entirely accurate or be changed in favour of a certain view. No source is useless, though some sources may be very inaccurate.

Informative and very accurate. A tool that would debunk claims from leftists or rightist from their political agenda.

This site is really good at sifting the wheat from the chaff. They call out everyone. Everyone shows up either "least biased" Left (nearest) center or Right (nearest) center, Left, Right, Far Left, or Far Right. I limit myself to posting from least biased, left center and right center. It protects me when I read an especially shocking headline, they usually come from the sites on the far ends of the spectrum. When they comed from the least biased... that's when shocking headlines are worth taking action. Check it out, decide for yourself. I'm left of Bernie Sanders, but I quit sharing Huffpo a year or two ago because they may not have leaned as far left as I did, but they slanted things a lot more than I do. The issue is really how much they slant the news. I can accept a little slant from either side...