Underlying mechanism used to 'rollback a GPO' to a previous version (4282513)

IS there any detailed documentation explaining the underlying mechanism used to rollback a GPO? i.e.

Is the whole GPO replaced in AD and SYSVOL or simply the deltas?

IS the version incremented in AD/SYSVOL or does AD handle that seamlessly?

Is the GPO data sourced from the SQL/file based repository or from the version control store, which is used to overwrite the existing GPO data?

The way the GPOAdmin rollback works is to extract the stored backup of the GPO the customer is rolling back to and importing this into the live object. This replaces the existing GPO in SYSVOL with the contents of the target backup, deltas are not used.

In this situation the major version of the GPO is incremented as well when the backup deployment is completed.

Due to the structure of GPMC it is not possible to roll back the version number in SYSVOL, the next major version will be used instead.