I remember that the question was about in-game trainers and their Pokemon's IVs, and one of its answers cited this page: https://bulbapedia.bulbagarden.net/wiki/Talk:Joey
Was it this? https://pokemondb.net/pokebase/189269/is-joeys-rattata-really-in-the-top-percentage-of-ratattas?show=189269#q189269 I remember coming across it once. It is if Joey has "top percentage" Rattata w/ perfect IVs and 252 Evs in Speed and Attack. The BA used the Bulbapedia link above.