Grogu Appeared in Star Wars Rebels and We All Missed It!
Star Wars Meg https://www.youtube.com/watch?v=bYDSU55n9AU
The Mandalorian Season 3 finale might have been foreshadowed in the World Between Worlds Star Wars Rebels episode with Sabine, Ahsoka and Ezra Bridger. Grogu (The Child) appears in an engraving in the place that Palpatine wanted control over. Could he have been written then and teased for future stories?