A mrt file and a rct file in the location of the virtual hard disks.
Windows server backup 2016 hyper v.
To backup a vm just start a simple wizard select which vms from your hyper v server have to be backed up and where the backups are to be saved and specify the backup schedule.
These files appear per virtual hard disk and are there to stay.
Starting in windows server 2016 hyper v started supporting backup through the hyper v wmi api.
With windows server 2016 hyper v backup microsoft rises to the challenge.
Yes hyper v 2016 do not have gui you may check if the following method could connect to the hyper v server 2016 to manage the windows server backup with gui remotely.
On a server with gui management better to be server 2016 add the hyper v 2016 into the server manager.
This approach still utilizes vss inside the virtual machine for backup purposes but no longer uses vss in the host operating system.
Hyper v wmi based backup.
Windows server backup has the gui console wbadmin msc that allows to create and manage hyper v backups create backup schedule etc.