The end of the tape of Loki's life has "ETH-616" written on it. Earth-616 is the main universe of the Marvel comics.
Tom Hiddleston recommended adding Odin telling his sons he loves them from Thor: Ragnarok (2017) to the Time Theatre.
Kate Herron took care to showcase the Time Theatre video of Loki's life not as a simple montage, but as a play with actions and consequences.
The Josta soda Agent Mobius drinks in Time Theater 5 is one of the earliest energy drinks. Sold by PepsiCo from 1995 to 1999, it was discontinued with no clear explanation why.
Concept art shows that Rocket Raccoon was planned to make a cameo appearance as a variant while Loki is being transferred through the TVA.