@TheMultiBrony21
Unlikely for panties to have a seam right in the middle. Even more so when the seam doesn’t go from edge to edge like a connecting seam must, but terminates, which means it’d have to be a dart, which would make no sense, since it wouldn’t improve the fit in any meaningful way, would compromise the integrity of the item, would be potentially irritating to the wearer, and would be easy to replace with the more standard and less material waste inducing approach.
It’s a crease.
Therefore, it’s a cameltoe.