The command is deprecated, as per NEWS of 254. Let's go one step further
and remove it from the help text and man page, so that people are not
inspired to use it at this time anymore.
This is how we usually have done this before: remove it from visibility,
but support it for a while still.
As mentioned in the NEWS entry, it seems to see very little use, but adds
complexity in our code. It was added mainly with the goal of making it easier
for people using grub2 to modify their boot configuration, but grub2 is gaining
support for BLS snippets. On the systemd side, we now have credentials. So
let's deprecate this, and if there's no outcry, remove it in a few releases.
Lennart Poettering
Zbigniew Jędrzejewski-Szmek