At the supermarket, I see regular frozen fries with instructions to cook in the fryer or in a pan.
And there are 'oven fries', to bake in the oven.
What makes 'oven fries' ... "oven" fries? I'm assuming it's something different with the pre-cooking and the oil, but it's just a guess
They have additional ingredients which make the fries more crispy than they would otherwise be -- often this involves cornstarch. For example, America's test kitchen has a popular recipe where you use a cornstarch slurry to make fries that taste like deep fried but use very little oil. The store bought versions similarly use cornstarch with other ingredients to have the same effect.
Fun Fact: The fast food giant Wendy's changed their fry formula in 2021 because they were getting a lot more delivery orders for fries, and typically fries become very sad very quickly. Their new fries are advertised to be more crispy for a longer time. By using archives ( https://web.archive.org/web/20201021020003/https://fastfoodnutrition.org/wendys/natural-cut-fries/medium compared to https://fastfoodnutrition.org/wendys/natural-cut-fries/medium ), you can see a major ingredient change was the addition of starches.
