With iOS, certificates are installed as part of profiles. Deleting a certificate means removing the profile.
When an iPhone with profiles is backed up, and then the backup is restored to a new device, the profiles are no longer visible under Settings > General > Profiles. So, they can't be deleted via the usual way.
The certificates however get restored to the device. One can see them e.g. under Settings > General > About > Certificate Trust Settings.
Hence my question: How can these certificates be deleted from the device?