This. Facebook agreeing to work with German government to do something about “racism” comments in German version (read: FB users talking about Cologne attacks that weren’t covered by mainstream press at all for weeks). FB blocking links to a mainstream respectable media’s article about freedom of speech in Czech version.
I have no doubt that FB doesn’t consider it bias. They’re righteous and seeing that attitude all over the supposedly “liberal” sphere is frightening.
https://en.m.wikipedia.org/wiki/Children_Overboard_affair
Which was a release of wrong information that demonised refugees for supposedly throwing their children into the water to blackmail the Howard government into letting them into Australia. This was released by Peter Reith, but it was subsequently revealed it was nothing of the sort, but it helped create a moral panic that boosted the electoral prospects of the Howard government, who subsequently won. It wasn't checked carefully by media organizations who ran the story - so it indeed got out of hand.
Which answered his question.
Because the International Facebook community are sharing and commenting on it organically, or because a group of liberal curators decide that's what Facebook users will see in the trending column?
As far as I understand, it's not the news that's being promoted (let's display this article on global warming, for example) that's the issue here, it's the news that's being suppressed (this Donald Trump post is getting popular, but I don't like his views so let's not display it).
Example #1: When a prominent American conservative does something like shutdown the government instead of compromising (remember compromising gets you booted at the next elections see: Paul Ryan). To most of the world (liberal and conservative), this is nuts. Facebook bubbles news reports about how "crazy" this is to the top. American news media will most likely call this a liberal bias when really it's just an international one.
Example #2: If facebook, editorializes a giant Ice-sheet melting and how that is related to anthropogenic global warming (something most International conservatives have accepted), most American conservatives will call that to be liberal bias. Note that this is not about policy decisions, most international conservatives don't agree with Carbon Taxes for instance, but one of just straight facts and assumptions.