LRV stands for Light Reflective Value. It is a scale from 0-100 and it measures the amount of light a color reflects. Zero being the darkest black and 100 being the brightest white.
Sherwin Williams Krypton sits at 52 which makes it a mid-toned color. Typically 60 and higher is considered a bright color, 30-60 is mid-toned.
Being a mid-toned color, especially at the top of the mid range, basically means that it has a good depth of color but is still light and bright.