openSUSE Tumbleweed has officially replaced its traditional GRUB2 boot loader with GRUB2-BLS when installing the system via YaST. It is a variant of the traditional GRUB2 that supports the Boot Loader Specification (BLS) — a modern standard defining how Linux systems store and manage boot entries.

Instead of using a single large configuration file like grub.cfg, GRUB2-BLS reads small, individual text files (called Type #1 entries) located in /boot/efi/loader/entries. Each file describes how to boot a kernel, including its initrd and command line options.