UMD differences between rollup and webpack

umd-code.js

function webpack(global, factory) {
  if (typeof exports === "object" && typeof module === "object") {
    module.exports = factory();
  } else if (typeof define === "function" && define.amd) {
    define("netlify-cms", [], factory);
  } else if (typeof exports === "object") {
    exports["netlify-cms"] = factory();
  } else {
    global["netlify-cms"] = factory();
  }
}

function rollup(global, factory) {
  if (typeof exports === "object" && typeof module !== "undefined") {
    module.exports = factory();
  } else if (typeof define === "function" && define.amd) {
    define(factory);
  } else {
    global["netlify-cms"] = factory();
  }
}