Those products are not labeled for grass of any kind, commercial or residential. Remember, the label is the law.
They are not the same product either. They have the same technical ingredient (mesotrione) but are formulated differently to be most effective for their specific application (ag vs. turf). A quick look of the label shows Tenacity has a label limit of 16 fl oz/A per year whereas Explorer has a label limit of 7.7 fl oz/A per year. Much of this has to do with the crop and fate in the soil.
One easy way to tell they are not the same product: look at the EPA registration number on the title page of any pesticide. If the numbers are the same, it's the exact same product. Syngenta, for example, makes a PGR called Primo MAXX with an EPA Reg. No. of 100-937. Syngenta also makes a private label PGR called Podium with an EPA Reg No. of 100-937. Same exact product. Easy way to tell if there is a difference when comparing products.