Document this rudamentary chain loader, and note it's deprecated.
Document the boot sequence when loader.efi is used. Document what is
searched, when and how. Document the variables it provides, and the
unique variables used by it.
Note: loader.efi.8 is super lean at the moment.
Should this mention the XXX should be replaced with an architecture specific name?
It might be useful to add the caveat that some firmware is unable to set a non-default boot location (at least via the runtime services). Many arm/arm64 boards with only one storage media are unable to set the needed variable to change the boot path.