The uglified umd preamble inserted by Browserify, broken down to a line by line interpretation.

umd.js

require=(
// t = mapping
// n = cache?
// r = entry points?
function e(t,n,r){
  // s = global require
  // o = module name
  // u = ???
  function s(o,u){
    // can we find it in the cache?
    if(!n[o]){

      // can we find it in the bundle's module index?
      if(!t[o]){

        // if we can't find it in the cache or the full list, throw an error
        var a=typeof require=="function" && require;
        if(!u&&a)return a(o,!0);

        if(i)return i(o,!0);

        var f=new Error("Cannot find module '"+o+"'");
        throw f.code="MODULE_NOT_FOUND",f
      }

      // 'l' is the module - we cache it in 'n[o]'
      var l=n[o]={exports:{}};

      // execute the module, passing (require, module, exports)
      t[o][0].call(l.exports,

        // require
        // the version passed to each module is different than the global require
        function(e){
          // look up 'e' in our dependencies
          // t[o][1] = current module's dependencies
          // the resulting 'n' will be an index
          var n=t[o][1][e];
          // if 'n' exists, then look up the module with that index
          //   otherwise, look up the module with the exact string we were passed
          return s(n?n:e)
        },

        // module, exports
        l, l.exports,

        // global require, module index, module cache, entry points
        e, t, n, r)
    }

    // if it's in the cache, just return it
    return n[o].exports
  }

  // for each entry point, require it
  var i=typeof require=="function"&&require;
  for(var o=0;o<r.length;o++)
    s(r[o]);
  return s
})({

  // example of 1 module
  // browserify will create an entry for each file it packs into the bundle
  1:[
    function(require,module,exports){ ... }, // module code gets wrapped in this
    {} // dependencies get stored here
  ]
}, // end of module index

{}, // module cache

// entry points that get run immediately
[149,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23])