[CTDOCodebases]

If I remember correctly iPhone apps used to use the devices SSL certificates so you as a user could install your own and man-in-the-middle the traffic to see what was being sent. AFAIK now the apps use certificate pinning.

[floam]

Certificate pinning is actually rarer today than it was a few years ago. You see it mostly in bank apps, and some system services. It’s not a best practice.

[saagarjha]

Apps can choose to do what they want.