Source is Wikipedia’s (de facto official) main list of reliable, unreliable and banned sources: en.wikipedia.org/w/index.php?title=Wikipedia:Reliable_sources/Perennial_sources&oldid=962008454
Excellent in-depth article from yesterday: Wikipedia formally censors The Grayzone as regime-change advocates monopolize editing
Whitney Webb’s great article from 2019: How a Small Group of Pro-Israel Activists Blacklisted MintPress on Wikipedia
ss: Wikipedia maintains “a non-exhaustive list of sources whose reliability and use on Wikipedia are frequently discussed”. Sources can be classified as “Generally reliable in its areas of expertise”, “No consensus, unclear, or additional considerations apply”, “Generally unreliable”, “Deprecated” (i.e. banned) and “Blacklisted”. Since pro-war sources and corporate MSM are preferred, a lot of bias on Wikipedia comes from its biased sources and biased editors.