Secret Android Phone Codes You Didn't Know Existed

Did you know about these before?

Time Stamps:
0:00 - Intro
0:32 - Universal “MMI” Codes
1:05 - Android-Specific Codes
1:40 - 4636 (Testing Menu)
4:01 - 225 (Calendar Info)
4:23 - 426 (FCM Diagnostics)
4:56 - 886266344 (Visual Voicemail Config)
5:43 - 729 (Pet Mode)
6:23 - 2627 (Cell Broadcast Testing Mode)
6:54 - 828282 (Telecom Developer Menu)
7:33 - 8477 (Pro Tips)
7:53 - Carrier-Specifc Codes
9:15 - There Are More Out There