Just out of curiosity, I've noticed that since iPadOS 15.4.1(Should be), Swift Playgrounds has been able to run self-written Swift apps on the device. It can be seen through Filza's app manager, and using the uicache command, one can also find that the corresponding app is registered with a "mobile" identity. I wonder if TrollStore might use a similar approach to allow apps to be opened when they are registered with a mobile identity.