Breakpoints different from documentation and other websites

Created by: DanielRuf

getbootstrap.com

alistapart.com

using the (recommended) breakpoints from http://getbootstrap.com/css/#grid-media-queries

also why is there ,max.width:767px and max-width:768px in bootstrap.css? This makes little sense?

Or min-width:480 and min-width:481px

I am using the following extension in Google Chrome: https://chrome.google.com/webstore/detail/responsive-inspector/memcdolmmnmnleeiodllgpibdjlkbpim