title: What is "{.tmp,app} " in Yeoman generator?
body: <p>I am getting started with the Yeoman workflow, but I can't seem to completely understand the "alternate search path" for the usemin task in the index.html file. For example, there are 2 blocks generated with the 'yo angular' command:</p>
  
  <pre><code>&lt;!-- build:js scripts/modules.js --&gt;
  &lt;script src="bower_components/angular-resource/angular-resource.js"&gt;&lt;/script&gt;
  &lt;script src="bower_components/angular-cookies/angular-cookies.js"&gt;&lt;/script&gt;
  &lt;script src="bower_components/angular-sanitize/angular-sanitize.js"&gt;&lt;/script&gt;
  &lt;script src="bower_components/angular-route/angular-route.js"&gt;&lt;/script&gt;
  &lt;!-- endbuild --&gt;
  </code></pre>
  
  <p>vs.</p>
  
  <pre><code>&lt;!-- build:js({.tmp,app}) scripts/scripts.js --&gt;
  &lt;script src="scripts/app.js"&gt;&lt;/script&gt;
  &lt;script src="scripts/controllers/main.js"&gt;&lt;/script&gt;
  &lt;script src="scripts/directives/multiselect.js"&gt;&lt;/script&gt;
  &lt;!-- endbuild --&gt;
  </code></pre>
  
  <p>Why does the second one have the {.tmp, app} "alternate search path" (what does it mean)? Thanks in advance.</p>