What does this button icon represent?

that's a toggle for Kilometers to Miles per hour and back

 

That's interesting, most of them don't have an icon and just say kph/mph

Wonder why this one is different?

 

Canadian or import?

 

That button graphic denotes that button controls the display brightness.

As Camper said, when that button toggles the speedo display between MPH and km/h the graphic is as shown below:

 

So then the button at the beginning circled in the red turns the brightness of the MFD up and down so I don't have to do it by bringing up the menu of the MFD but to do anything else to the MFD I have to bring up the menu like to change the contrast but I can change the brightness right from the button bypassing everything and I guess it's stuck in kilometers or miles per hour forever so this must be done unlike local market cars kilometer per hour cars Asian market European market something correct?

 

No, it changes the brightness of the CM, much the same as the brightness control wheel on the US model Prius. There are 3 levels of dimming – dim, dimmer, and dimmest – if you will or what have you. If you press and hold the button down it reverts to full brightness. Lastly the button only does anything when the lights are on.

Yes, the speedometer is fixed in km/h.