Use this page to verify that axe-core produces the correct colors for each blended background. If using Chrome, please ensure it is using the sRGB color profile by navigating to chrome://flags/, searching for "Force color profile" and setting it to "sRGB" (otherwise it uses the OS color profile which for Mac, which we believe is "Display P3 D65" and will produce the incorrect result color when blending).
For more information, see https://github.com/dequelabs/axe-core/issues/2924