sub make_ext_hash {
  my $mime = shift;
  my %ext = ();
  for my $name (keys %$mime) {
    my $desc = $mime->{$name};
    $ext{$_} = {
      icon => $mime->{$name}{icon},
      name => $name,
    } for @{ $desc->{ext} };
  }
  return \%ext;
}