The prebuilt files include `web/pdf_viewer.js` with some viewer APIs. Those are missing from type declarations.
const imageDecodersAMDName = "pdfjs-dist/image_decoders/pdf.image_decoders";
  const imageDecodersOutputName = "pdf.image_decoders.js";
  const componentsFileConfig = createWebpackConfig(defines, {
    filename: imageDecodersOutputName,
    library: imageDecodersAMDName,
    libraryTarget: "umd",
    umdNamedDefine: true,
  });
  return gulp
    .src("./src/pdf.image_decoders.js")
    .pipe(webpack2Stream(componentsFileConfig))
    .pipe(replaceWebpackRequire())
    .pipe(replaceJSRootName(imageDecodersAMDName, "pdfjsImageDecoders"));
}
function createCMapBundle() {
  return gulp.src(["external/bcmaps/*.bcmap", "external/bcmaps/LICENSE"], {
    base: "external/bcmaps",
  });
}
function createStandardFontBundle() {