http://search.cpan.org/grep?cpanid=ANDK&release=CPAN-1.9800&string=prompt&i=1&n=1&C=0

1079:            $CPAN::Frontend->myprint($prompts{proxy_user}) unless
+ $auto_config;
1081:            if ($CPAN::Config->{proxy_user} = prompt("Your proxy 
+user id?",$default)) {
1082:                $CPAN::Frontend->myprint($prompts{proxy_pass}) un
+less $auto_config;
1087:                    $CPAN::Frontend->myprint($prompts{password_wa
+rn}) unless $auto_config;
1089:                $CPAN::Config->{proxy_pass} = prompt_no_strip("Yo
+ur proxy password?");
[download]

lib/CPAN/HTTP/Credentials.pm

36:    my $username_prompt = "\nProxy authentication needed!
42:        _get_username_and_password_from_user($username_prompt);
56:    my $username_prompt = "\nAuthentication needed!
63:        _get_username_and_password_from_user($username_prompt);
71:    ExtUtils::MakeMaker->import(qw(prompt));
72:    $username = prompt($username_message);
81:    $password = prompt("Password:");
[download]