Quality is tested and indicated as five LEDs in terms of  "percent of water in the brake fluid".

LED Display:  

Green :                              No water. - OK.

Yellow:                               Less than 1% of water. - Warning.

Yellow/Yellow:                    Approx. 2% of water. - Warning.

Yellow/Yellow/Red:            Approx. 3% of water. - Oil should be changed.

Yellow/Yellow/Red/Red:    At least 4% of water. - Change the oil urgently.