In the Single Parents episode "Lance Bass Space Cump" (yes it's "Cump", not "Camp"), Sophie is going to camp. Her dad, Will, brings her to the camp bus and has a heartfelt (and comedic) goodbye with her. During all of this, he's prominently carrying a big manila envelope that says "Letters from Sophie".
I'm confused about what's supposed to be in the envelope. She didn't send him letters from camp yet, so they're not from her. Sophie isn't taking the envelope with her to camp, so it's not self-addressed-stamped-envelopes and blank sheets of paper for Sophie to write to Will. It looks relatively new - there are just a few wrinkles on it - so it doesn't look like it's letters from the past.
What is supposed to be in this envelope?