Comment # 10 on bug 1050953 from Fabian Vogt

(In reply to Dominique Leuenberger from comment #9)
> ListCachedUsers lists the users
> 
> > gdbus call --system --dest org.freedesktop.Accounts --object-path /org/freedesktop/Accounts --method org.freedesktop.Accounts.ListCachedUsers

It doesn't list *all* users here, which is the issue. It only lists the users
that "CacheUser" has been called for, with no option (apparent to me) to list
all available usernames.