Assuming the string to be modified is in $_:

$_ = do {my $t  = "";
            $t .= defined $1 ? do {(my $t = $1) =~ y/\\//d; $t} : $2
                  while /((?:[^\\]+|\\(?!\*))+)|(\\\*(?:[^*]+|\*(?!\\)
+)+\*\\)/g;
            $t
};
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Abigail