Prefix{u,v}2={w,x}:b:1
Prefix{u,v}2={w,x}:{y,z}:1
Prefix{u,v}2={w,x}:b:2
Prefix{u,v}2={w,x}:{y,z}:2

##</code><code>##

c:\@Work\Perl\monks\NorthernFox>perl -wMstrict -MData::Dump -le
"my @proto_globules = (
   'Prefix{u,v}2={w,x}:b,{y,z}:1,2',
   );
 ;;
 my $rx_comma_in_curlies = qr{ { .*? , .*? } }xms;
 ;;
 my $rx_globmeta = qr{ [\[\]{}*?~] }xms;
 ;;
 my %globize = ('=' => '={',  ':' => '}:{',  '' => '}');
 ;;
 for my $globule (@proto_globules) {
   print qq{A: '$globule'};
   $globule =~ s{ ($rx_comma_in_curlies) }
                { (my $r = $1) =~ s{,}{\\,}xmsg;  $r; }xmsge;
   $globule =~ s{ (?= $rx_globmeta) }{\\}xmsg;
   print qq{B: '$globule'};
   $globule =~ s{ ([=:] | \z) }
                { print qq{S: '$1'};  $globize{$1}; }xmsge;
   print qq{C: '$globule'};
   my @globs = glob $globule;
   dd 'DD:', \@globs;  print '';  next;
   }
"
A: 'Prefix{u,v}2={w,x}:b,{y,z}:1,2'
B: 'Prefix\{u\,v\}2=\{w\,x\}:b,\{y\,z\}:1,2'
S: '='
S: ':'
S: ':'
S: ''
C: 'Prefix\{u\,v\}2={\{w\,x\}}:{b,\{y\,z\}}:{1,2}'
(
  "DD:",
  [
    "Prefix{u\\,v}2={w\\:b:1",
    "Prefix{u\\,v}2={w\\:b:2",
    "Prefix{u\\,v}2={w\\:{y\\:1",
    "Prefix{u\\,v}2={w\\:{y\\:2",
    "Prefix{u\\,v}2={w\\:z}:1",
    "Prefix{u\\,v}2={w\\:z}:2",
    "Prefix{u\\,v}2=x}:b:1",
    "Prefix{u\\,v}2=x}:b:2",
    "Prefix{u\\,v}2=x}:{y\\:1",
    "Prefix{u\\,v}2=x}:{y\\:2",
    "Prefix{u\\,v}2=x}:z}:1",
    "Prefix{u\\,v}2=x}:z}:2",
  ],
)

##</code><code>##

    still active! -------+------------+
                         |            |
                         v            v
C: 'Prefix\{u\,v\}2={\{w\,x\}}:{b,\{y\,z\}}:{1,2}'
                    ^        ^ ^          ^
                    |        | |          |
 in added curlies --+--------+-+----------+