blend-update-menus behaves differently depending on who run the command:
If it's called by a user, it adds and keeps updated menu entries for the
user who runs it.
If it's called by root, it adds and keeps updated user's menu entries
(see menu package for users' menus) for all users who belong to the
group of the specified Debian Pure Blend, or only for a
specified user, depending on which parameter is passed to the script.
one of the installed Blends, listed in /etc/blends/, for example (if installed):
a user present on the system and belonging to a Blend