Color space

A Color space defines what range of colors and what gamma curve you have available. Two common ones for game development is sRGB and Linear RGB. sRGB is made to be viewed on monitors, to achieve this, it can change your sourcematerial to fit. That's usually not a problem if the texture is used just for color. However if it's used for shadermath or masks, it's usually better to set it to Linear to make sure the values stay the same.

https://en.wikipedia.org/wiki/SRGB