It appears that the official chrome webstore extension by Rob W is outdated. It was last updated in 2019. 

const skipBabel =
      bundleDefines.SKIP_BABEL || /\/\*\s*no-babel-preset\s*\*\//.test(content);
    content = preprocessor2.preprocessPDFJSCode(ctx, content);
    content = babel.transform(content, {
      sourceType: "module",
      presets: skipBabel ? undefined : ["@babel/preset-env"],
      plugins: [
        "@babel/plugin-transform-modules-commonjs",
        babelPluginReplaceNonWebpackImports,
      ],
      targets: BABEL_TARGETS,
    }).code;
    const removeCjsSrc =
      /^(var\s+\w+\s*=\s*(_interopRequireDefault\()?require\(".*?)(?:\/src)(\/[^"]*"\)\)?;)$/gm;
    content = content.replace(removeCjsSrc, (all, prefix, interop, suffix) => {
      return prefix + suffix;
    });
    return licenseHeaderLibre + content;
  }
  const babel = require("@babel/core");
  const ctx = {
    rootPath: __dirname,
    saveComments: false,
    defines: bundleDefines,
    map: {
      "pdfjs-lib": "../pdf",
      "pdfjs-fitCurve": "./fit_curve",
    },