I work on a MacBook Pro with a Retina display as my main computer. I was looking for a convenient way to test what my sites looked like on a 1X display. There was no great solution, so I made one.
I call it Blind and it’s a 1X browser for Retina displays. It comes with a bookmarklet for your normal browsers to easily send sites to Blind with one click.
For me, this has been a good way to proof sites in 1X when working with a Retina display. I eventually stopped supporting Blind as the app became less relevant over time.