Mishaal Rahman: Android is adding native support for repair mode, a feature that "creates a secure environment to protect the user's privacy when the device is being repaired."
The "problem" is that android doesn't just encrypt data; it uses full disk encryption. That means, only things absolutely necessary are accessable before the password is entered. This absolutly necessary stuff does (to my knowledge) not include any diagnostics tools a technician would need to verify the existence of a problem or wether it has been solved.
The new mode would probably just be a way to get more of the system decrypted so the technician can do their job.
no, this isn't fully correct. The first time you boot your phone, you have to unlock with your PIN. This decrypts your user "partition" that holds all your data. Imagine all the crap you produce including apps goes in that partition. The base operating system, what you get from the factory, is in a separate partition that is NOT encrypted by you. So what this repair mode does is basically take advantage of the already built-in DSU functionally for booting generic kernel images (GKI) and instead use it to boot a copy of your system. Your personal data remains fully encrypted.