Wordfence Security reports this:
Modified plugin file: wp-content/plugins/w3-total-cache/pub/js/options.js
This file belongs to plugin "W3 Total Cache" version "0.9.2.10" and has been modified from the file that is distributed by WordPress.org for this version. Please use the link to see how the file has changed. If you have modified this file yourself, you can safely ignore this warning. If you see a lot of changed files in a plugin that have been made by the author, then try uninstalling and reinstalling the plugin to force an upgrade. Doing this is a workaround for plugin authors who don't manage their code correctly. [See our FAQ on http://www.wordfence.com for more info]
This screenshot shows how this file is modified: http://screencast.com/t/ChhMQstuh1HA
I updated both Wordfence and W3TC to latest version lately. Also, my site is under attack lately as wordfence locks out around 30 people almost every day that try to log in as admin.
So, I'm not sure if that modification is normal, or made by a hacker.