Device codes should be backed up. Regardless of whether they are HomeKit or Matter devices. Because without a code, the devices are unusable and cannot be set up again.
Controller for HomeKit offers a very convenient option in the latest version 6.1. In addition to scanning the QR code via the camera or entering it manually, a photo can also be imported from the library. A feature that we still sorely miss in the HomePass beta.
For example, Eve Systems saves the code as a photo when migrating to Matter. In Controller for HomeKit, this can now be imported quickly and easily.
Also new is support for critical notifications. This makes the custom message capabilities introduced with version 6.0 even more powerful.