I could not immediately see their method for ranking factuality.

They claim on their website that they don't do most of their own fact checking:

"Media Bias/Fact Check rarely conducts original fact checks as many other sources are faster and do a better job. We primarily rely on fact-checkers affiliated with the International Fact-Checking Network ( IFCN)."

According to Media Bias/Fact Check's Wikipedia page, writers at the Poynter Institute, developer of the IFCN, have made the following statement: "Media Bias/Fact Check is a widely cited source for news stories and even studies about misinformation, despite the fact that its method is in no way scientific."

It is interesting that one of Media Bias/Fact Check's criteria is biased wording and then they made the following assessment about Times of Israel: "The Times of Israel covers Israeli and regional news with minimally loaded language..." Meanwhile, the caption for the top headline on the Times of Israel at this time is: "PM’s office says families of those slated to be freed have been notified * G7 foreign ministers urge further extension of ceasefire between Israel and Gaza-ruling terror group" Terror group does not sound like minimally loaded language. Now if the people who created the criteria to measure biased language are not concious of the fact that terror or terrorist in place of militant or rebel is biased language, then that will skew results through algorithmic bias.