>>14156856Originally established in 1994 by the Interactive Digital Software Association (now the Entertainment Software Association), it had rated over 8,000 titles by 2003. The decision to found the ESRB was influenced by violent content found in games such as Mortal Kombat and Night Trap and other controversial video games portraying violent or sexual situations at the time.
That's what I know, but according to the seller before the ESRB existed, there was a video game rating board that existed somewhere around the Genesis/SNES era. However, they did not last long as there was no organization or standardization for the ratings themselves. They were also not aligned with every game system. The ESRB eventually came along and formally set-up a ratings system that is not unlike movie ratings.
However, there was a window period that exists where games had no ratings on them, and the Game Boy was one of the systems affected by this.
Also the ESRB went through a graphic design revision. There was originally a "White Outline" Letter set-up. However, they eventually moved to a solid black letter system, as referenced here. Essentially what this all means is that there are at least three confirmed variant packaging styles for Pokemon Yellow; No ESRB, Original ESRB, and Modern ESRB.
