Why does Grub2 present twice/double menuentry for each ostree entry

Hi all !

I have three Silverblue deployments

$ rpm-ostree status
State: idle
Deployments:
● ostree://fedora:fedora/34/x86_64/silverblue
                   Version: 34.20210423.n.0 (2021-04-23T08:10:25Z)
                
  ostree://fedora:fedora/34/x86_64/silverblue
                   Version: 34.20210423.n.0 (2021-04-23T08:10:25Z)
                
  ostree://fedora:fedora/34/x86_64/silverblue
                   Version: 34.20210423.n.0 (2021-04-23T08:10:25Z)
          

They match the three ostree entries

$ sudo tree /boot/loader
/boot/loader
├── entries
│   ├── ostree-1-fedora.conf
│   ├── ostree-2-fedora.conf
│   └── ostree-3-fedora.conf

Thus using blscfg , as I understand it, I should have the corresponding GRUB2 menuentries:

menuentry 'Fedora 34.20210423.n.0 (Silverblue) (ostree:0)' 
menuentry 'Fedora 34.20210423.n.0 (Silverblue) (ostree:1)' 
menuentry 'Fedora 34.20210423.n.0 (Silverblue) (ostree:2)'

So why does GRUB2 present me with 6 menuentries ? they seem doubled …
What are they for ?

Thanks

See this:

And:
https://fedoraproject.org/wiki/Changes/BootLoaderSpecByDefault#Config_files_provided_by_kernel.2C_grub2-switch-to-blscfg.2C_and_zipl-switch-to-blscfg