these include features to parse and render HTML and CSS, manipulate the DOM, and parse JavaScript. While this code is actively developed, it is often only developed and reviewed by a single organization (e.g., the Chromium code is only modified by Google developers while the RIM code is only modified by the Blackberry developers). Therefore we looked only at the patches that change non-platform-specific files within WebCore; this reduced the total number of patches considered from 34,749 to 17,170. We also eliminated those patches that had not been reviewed, i.e., patches that had only review? flag. This filter further narrowed the input to 11,066 patches.