Wikipedia is a good source for certain kinds of information. If you ask it about anything political it's going to be from a certain slant and the most informative part of the page will be the Talk page which explains what people would like on the page that isn't there, or shouldn't be on the page but is
What examples of this are there? I've usually found Wikipedia to be quite equal opportunity, well rounded, and factual.
They have their NPOV[1] policy, and seem impressively unbiased to me, given the various divisive situations they have to try to cover.
[1] https://en.m.wikipedia.org/wiki/Wikipedia:Neutral_point_of_v...
Just because the policies are supposed to be neutral doesn't mean the resulting work is guaranteed to be truly neutral. Whether something is definitely a fact or an opinion can be very fluid, and you can play a lot with the amount of attention each viewpoint gets. Even a "neutral" article can end up reading completely differently when one viewpoint is very detailed and described in a fact-like way, while another only gets a short summary which reads as if it is a fringe opinion. And even when you are trying to be neutral, it is incredibly hard to avoid your output from getting shaped by the culture you are surrounded with.