The source code shows that the Android Debug Bridge (adb) backup and restore commands may be removed in future versions of Android.
People who have developed Android may be familiar with adb. It is a tool for debugging Android devices. With USB debugging mode or Wi-Fi, adb connects Android IDE and Android devices, developers can use various kinds of IDE commands to operate the phone, including restart, access to recovery, access to fastboot and push files.
The latest AOSP source master branch has a code-reviewed and marked Merged commit “Add deprecation warning to adb backup/restore” display, and support for adb backup and restore commands will end. A deprecation warning is displayed whenever a user attempts to run a backup or restore an adb command.
This means that the two adb commands will be removed in future versions of Android.