For context, the "lab leak theory" states that the SARS-CoV2 virus, the pathogen responsible for the COVID-19 disease, was created in a laboratory in Wuhan, China. Until recently, Facebook has been banning or discreetly censoring (shadow-banning) posts promoting this theory. The theory is now being taken more seriously by those on the political left in the U.S., and Facebook changed its policy and said that it will no longer remove these posts. (But I don't know if we can trust Facebook to be honest at this point.)