Most gravel bikes come with a bar that has a flare to the drops. Just how much varies, but it's designed so that if you're descending in the drops you have more steering control. If you're coming from an MTB the width probably won't faze you, but it can feel a bit odd for a reformed roadie. A wide flare can put the brake levers at an angle that doesn't feel right for the road rider too.
The drop from the tops to the drops is also likely to be less than with road bike bars, so that when riding in the drops you're in a more upright position and can shift your balance and spot obstacles better.
Check out our guide to the best gravel bike handlebars if you want to see what's available.