I think they're talking about coffee, iirc there are some studies that show it helps with liver cirrhosis which can cause jaundice
Plectranthus barbatus
It was more a referende to the act of boiling water. The observer at that point might not yet know if it's just a correlation or not. Just gathering information.
Milk thistle is the historical one. NAC is the modern one.
Milk thistle supplements are popular for liver health.