The notion that gasoline is added to denatured alcohol is simply not true.
It is true. See the reference linked above.
See the attached data sheets for two examples of denatured alcohol for sale in the US. As wkb says, denatured alcohol means simply making ethanol undrinkable. This stuff is often used in science labs; a mix as crude as gasoline would not be suitable.
Your datasheets contain formulas for "specially denatured alchohol", SDA. These formulas are very restricted in their availability, for example to industry, food, cosmetics and pharmaceutical uses, and science labs. SDA is simply not available for the general public to purchase.