use strict;
use warnings;

BEGIN {our @usedModules; unshift @INC, sub {push @usedModules, [@_]; return undef;}}

our @usedModules;

...

my $versions = '';
for (@usedModules) {
   my $name = $_->[1];

   $name =~ s/\..*//;
   $name =~ s|[\\/]|::|g;
   
   my $version = eval{eval "\$$name\::VERSION"};
   $versions .= "$name \t$version\n" if defined $version;
}

print $versions;