I spent hours googling this line because I thought something was wrong with my liver! But my gynac reassured me it's just pigmentation. It will fade, so try not to overthink it like I did.
That dark line is just because of pregnancy hormones increasing melanin. I had a very dark one too, but it faded completely within a few months of breastfeeding.
Just apply some pure olive oil or aloe vera gel after bath to keep it soft. It's totally natural, but if you feel severe itching or redness, then check with your doctor.
I totally get why you might feel worried seeing new marks on your body, I panicked too. But please relax, it's called linea nigra and it's 100% harmless.
