chrome/common/extensions/docs/templates/private/permissions/unlimited_storage.html

   1 Provides an unlimited quota for storing HTML5 client-side data, such as databases and local storage files. Without this permission, the extension or app is limited to 5 MB of local storage.
   2
   3 <p class="note">
   4 <b>Note:</b> This permission applies only to Web SQL Database and application cache (see issue <a href="http://crbug.com/58985">58985</a>). Also, it doesn't currently work with wildcard subdomains such as <code>http://*.example.com</code>.
   5 </p>