This is very confusing as seen in #12974 or #12906. My suggestion would be "legacy."
},
    function () {
      console.log();
      console.log("### Creating minified (ES5) viewer");
      var defines = builder.merge(DEFINES, {
        MINIFIED: true,
        GENERIC: true,
        SKIP_BABEL: false,
      });
      return buildMinified(defines, MINIFIED_ES5_DIR);
    }
  )
);
async function parseMinified(dir) {
  var pdfFile = fs.readFileSync(dir + "/build/pdf.js").toString();
  var pdfWorkerFile = fs.readFileSync(dir + "/build/pdf.worker.js").toString();
  var pdfSandboxFile = fs
    .readFileSync(dir + "/build/pdf.sandbox.js")
    .toString();
  var pdfImageDecodersFile = fs
    .readFileSync(dir + "/image_decoders/pdf.image_decoders.js")
    .toString();
  var viewerFiles = {
    "pdf.js": pdfFile,
    "viewer.js": fs.readFileSync(dir + "/web/viewer.js").toString(),
  };
  console.log();
  console.log("### Minifying js files");
  var Terser = require("terser");
  var options = {