docs: protected final Property parseVendorExtensionContent( String vendorExtension ) {
          Matcher matcher = VENDOR_PATTERN.matcher(vendorExtension);
          if (!matcher.find()) return null;
          String vendorName = removeQuotes(matcher.group(1));
          String vendorValue = removeQuotes(matcher.group(3));
          assert vendorName != null;
          assert vendorValue != null;
          assert vendorName.length() != 0;
          assert vendorValue.length() != 0;
          return context.getPropertyFactory().create(nameFactory.create(vendorName), vendorValue);
      }