How to dump iOS app's source code

Reverse engineering apps is made a lot easier with the source code, but apps distributed through the App store are encrypted with FairPlay encryption, making decompilation much harder. Our salvation lies in jailbreaking, because in order to run the app the unencrypted version has to be loaded into memory. We can add in code to take that unencrypted version in memory and download it. Adding alias20.gitlab.io/apt as a source in Sileo allows us to install a rootless version of bfdecrypt which does just that. Once it's installed go to Settings > bfdecryptor and enable it for whatever app you're trying to download, and the next time we open the app it will automatically save the decrypted version for processing. Here's an example for Fitness SF from this post.