With a script that takes just a few lines, you can literally save yourself and your team hours of work.
The first step in this recipe was adding the development team to your Xcode project. This is needed because signing the app requires a development team.
Then you generated an app-specific password. This is a password that you can use with your Apple ID and allows you to sign in to your account from any app. So, instead of using your main password, you can give access to other apps (in this case fastlane). In this way, when a security breach happens, you only need to remove the password that was compromised and everything else will keep working securely.
Each iOS app contains an Info.plist file, where you keep configuration data. There you put the following node:
<key>ITSAppUsesNonExemptEncryption</key>
<false/>
The purpose of this node is to tell TestFlight that you are not using any special encryption tool within the app; some encryption tools cannot...