efivarfs - a (U)EFI variable filesystem
  
  The efivarfs filesystem was created to address the shortcomings of
  using entries in sysfs to maintain EFI variables. The old sysfs EFI
  variables code only supported variables of up to 1024 bytes. This
  limitation existed in version 0.99 of the EFI specification, but was
  removed before any full releases. Since variables can now be larger
  than a single page, sysfs isn't the best interface for this.
  
  Variables can be created, deleted and modified with the efivarfs
  filesystem.
  
  efivarfs is typically mounted like this,
  
  	mount -t efivarfs none /sys/firmware/efi/efivars
  
  Due to the presence of numerous firmware bugs where removing non-standard
  UEFI variables causes the system firmware to fail to POST, efivarfs
  files that are not well-known standardized variables are created
  as immutable files.  This doesn't prevent removal - "chattr -i" will work -
  but it does prevent this kind of failure from being accomplished
  accidentally.