How to get "filesystem" grub2 core.img

With GRUB2 there seems to be something new that i do not know.
I used alma to create a manjaro-installation on an usb-stick. This works very nice. When viewed with gparted the partion 2 shows a filesystem i didn’t know. The entry says this is filesystem “grub2 core.img” it has size 1.00MiB and is marked as bios_grub. Now with google i found some mentionings of “grub2 core.img”. But nothing that explains how to get such a partition.
I do ask because i am in the process of extending my pc with a new ssd. I want to partition it like “alma” did.