What do you suppose this is doing?

The last two lines are from the original Crypt::PasswdMD5 code. I thought $Magic = q/$1$/;

prefaced the unix_md5_crypt string and was also added to the password along with the salt prior to encrypting. The other

$itoa64 = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
is used for the 'to64' subroutine which is then used by the 'unix_md5_crypt' subroutine.

I tried replacing the lines with

my $Magic = shift @ARGV;

and

my $Magic = shift; 
$Magic = @ARGV;
[download]

but I kept getting this error.

"Error executing class callback in prerun stage: No filters found for 'cpwdmd5'...."