The American Comics Code is a pre-War organization dedicated to comic books. Their seal of approval can be seen on certain copies of the Unstoppables comic book line, published by Hubris Comics.
The American Comics Code is mentioned only in Fallout 4 and Fallout 76.
As seen on various Unstoppables titles.
Behind the scenes
The American Comics Code is a reference to the real life Comics Code Authority, an organization that existed from 1954 to 2011 and functioned as a self-regulating body for comic publishers' content.