Many of the existing Grease Pencil “Layer Specials” commands can be found in the convenient Grease Pencil: Design Dopesheet’s Layer Context Menu. By adding these options to the Layer Context menu, they are much more easily accessible where you want them: in the layers! To learn more about each command, check out the Official Blender Documentation on the Layer Specials.

Delete Selected Layers is a user experience improvement from the native Layer Remove button (—) as it works with multiple layers, while the Layer Remove button only works with a single active layer.