I've heard of the double CGG codon at the furin cleavage site. This genetic marker is indeed peculiar among coronaviruses, which could be used to support either something unexpected from mother nature or something deliberate from labs. Which one is true, I honestly don't know.

I'm not sure anyone knows what's the truth though, since all we have about the origin of Covid-19 are speculations. For me, I have 60% confidence that the origin is natural and 40% is gain-of-function experiment.

(Even if it leaks from the lab, as long as the virus has not undergone gain-of-function experiments, I still consider it a natural origin.)

Not sure if that helps, but I appreciate your trust in me, thanks for commenting :)) Just let me know if anything isn't clear.