This is very confusing as seen in #12974 or #12906. My suggestion would be "legacy."
return Promise.all([
        pdfManager.ensureDoc("documentInfo"),
        pdfManager.ensureCatalog("metadata"),
      ]);
    });
    handler.on("GetMarkInfo", function wphSetupGetMarkInfo(data) {
      return pdfManager.ensureCatalog("markInfo");
    });
    handler.on("GetData", function wphSetupGetData(data) {
      pdfManager.requestLoadedStream();
      return pdfManager.onLoadedStream().then(function (stream) {
        return stream.bytes;
      });
    });
    handler.on("GetStats", function wphSetupGetStats(data) {
      return pdfManager.ensureXRef("stats");
    });
    handler.on("GetAnnotations", function ({ pageIndex, intent }) {
      return pdfManager.getPage(pageIndex).then(function (page) {
        return page.getAnnotationsData(intent);
      });
    });
    handler.on("GetFieldObjects", function (data) {
      return pdfManager.ensureDoc("fieldObjects");
    });
    handler.on("HasJSActions", function (data) {
      return pdfManager.ensureDoc("hasJSActions");
    });
    handler.on("GetCalculationOrderIds", function (data) {
      return pdfManager.ensureDoc("calculationOrderIds");