Edits GRUB_CMDLINE_LINUX. GRUB menu generators normally add this value to every generated Linux menu entry, including recovery or rescue entries.

Use this for options that must be present whenever Linux boots, such as storage, root filesystem, LVM, filesystem flag, security, mitigation, or crashkernel options.

On BLS-based systems, existing boot entries may store options directly in BLS entry files, or reference $kernelopts, a GRUB environment value stored in grubenv. Webmin does not edit grubenv directly; when grubby is available, Webmin asks it to apply changes here to all existing BLS entries.