Paint colors don't inherently have undertones.
The way most people use the term undertone is to describe their own, personal, subjective perception of a color in their own unique context and lighting conditions. Again, has nothing to do with a color's actual, inherent attributes.
Which is exactly why you found so much, often inconsistent, information about gray paint colors on blogs and Pinterest. They're all guessing about what they think they see under their own random light sources; their individual, personal description of a color using the word undertone isn't a fact.
Light French Gray belongs to the Yellow hue family. That's a fact.
We can measure Light French Gray and get color data values that tells us - based on actual wavelengths - that Light French Gray belongs to the yellow hue family.
All colors belong to a hue family including colors of white and near neutrals like Light French Gray. Nothing is hidden or under anything.
Hue/hue family is incredibly straight forward and simple. After buying into the convoluted theories involving undertones, most people can't believe that identifying a color's core hue attribute is as easy as looking it up on easyrgb dot com or measuring it with a Color Muse, NIX or Color Reader.
But it is that simple.
It's so simple many color "experts" and designers don't want you know how easy it is because so many of them rely on marketing the ability to see undertones that all the poor slobs with "untrained eyes" can't see.
Claiming a special ability to see color "undertones" is THE ultimate Emperor has no clothes scam.
Every single color typically categorized as "gray" found in all commercial paint brands belongs to a hue family - none of them are "true" neutrals. And you can find grayed down colors from every single hue family in the visible spectrum - not just blue, green and purple.
As proven with Light French Gray that belongs to the yellow hue family. And that fact also explains why it could be perceived as having no perceivable hue bias. Colors of gray in the range from Yellow to Green on the color wheel you see up there are typically perceived as being the most neutral in appearance.
The only true, achromatic gray paint colors are made by GTI. They're spectrally balanced formulas to match Munsell N8, N7, and N5.
Q
Patio
Q