update readme. There's always *something* you overlook when making a …

…major release

README.md

@@ -16,6 +16,8 @@ Below the Sunless Sea are seas of a more dangerous sort: lakes of oil and the ma
 
 At the very foundation of the world lies an ancient impenetrable realm. There are signs that life once existed here but it is now long gone. Its dead hollows rest on a layer of Slade, a dense material impervious to conventional mining efforts.
 
+Unconventional methods of penetrating the Slade do exist, however. And should it be breached, the exotic Primordial cavern layer can be found beneath.
+
 ## Other Features
 
 The giant caverns generated by this mod differ slightly from the default giant caverns found in some mapgens, they use an additional source of noise to generate more ledges and horizontal floors. They also contain stalactites and stalagmites of various sizes - from single-node spikes decorating the default twisty tunnels to mountainous behemoths in the main caverns that can reach tens of meters in diameter and hundreds of meters in height.
@@ -36,4 +38,6 @@ The "[doc](https://forum.minetest.net/viewtopic.php?f=9&t=15912&p=240152)" mod i
 
 "[ropes](https://github.com/minetest-mods/ropes)" are very useful for navigating some of the large open spaces this mod provides.
 
-"[radiant damage](https://github.com/FaceDeer/radiant_damage)" greatly increases the danger of the Magma Sea if heat radiance is enabled, as well as several of the rare crystals in the deeper layers that emit Mese radiation if that damage type is enabled.
+"[radiant damage](https://github.com/FaceDeer/radiant_damage)" greatly increases the danger of the Magma Sea if heat radiance is enabled, as well as several of the rare crystals in the deeper layers that emit Mese radiation if that damage type is enabled.
+
+Adding "[named_waypoints](https://github.com/FaceDeer/named_waypoints)" and "[namegen](https://github.com/FaceDeer/namegen)" will provide some landmarks in the Underworld that a player can use to navigate by.