Pixar does many things exceptionally well, including how they carefully craft and hide Easter eggs such as "A113" throughout each one of their films. The studio, which kicked off its massive success with the beloved film Toy Story, is known for its animated pieces that touch the hearts of multiple generations. One way that they celebrate their accomplishments and their long history of impactful stories is through their innovative creation and inclusion of certain traditions that reference their history. Although ones, such as the John Ratzenberger cameo, have not been able to make their way into more recent movies, the A113 Easter egg has been present in every single Pixar film.

https://screenrant.com/pixar-movies-a113-easter-egg-every/