Basically you are trying to know file format using file
command.
file ./-*
Here, ./-*
this shell glob will pick up the all files which starts from -
(minus sign) and it will print the file format of the file.
In your case you are running this command to find the human readable file so that you can read password from it. You can read ASCII text file content.
More about file
command:
NAME
file — determine file type
SYNOPSIS
file [-bcEhiklLNnprsvzZ0] [--apple] [--extension] [--mime-encoding]
[--mime-type] [-e testname] [-F separator] [-f namefile]
[-m magicfiles] [-P name=value] file ...
file -C [-m magicfiles]
file [--help]
DESCRIPTION
This manual page documents version 5.25 of the file command.
file tests each argument in an attempt to classify it. There are three
sets of tests, performed in this order: filesystem tests, magic tests,
and language tests. The first test that succeeds causes the file type to
be printed.