Was doing weekly maintenance on my bike, and noticed some strange cracks (?) on my front wheel rim.

When I run my finger over the visible line, I feel nothing, everything is completely level. But when I use my fingernail then I can feel the crack.

Is this somekind of a paint crack? Or do I need to replace the entire front rim to a new one? About 1 500 km rode on this one-year-old bike.