looks like gzipped, it's only 1.9k

Author: jashkenas

index.html

@@ -112,7 +112,7 @@ <h2>Downloads <i style="padding-left: 12px; font-size:12px;">(Right-click, and u
         </tr>
         <tr>
           <td><a href="underscore-min.js">Production Version (0.3.3)</a></td>
-          <td><i>4kb, Packed and Gzipped</i></td>
+          <td><i>2kb, Packed and Gzipped</i></td>
         </tr>
       </table>
     </p>