Durability Grenades are now "special" Items (as before snowballs, eggs and clayballs) you can spawn them using a command (/grenade type amount). That way normal eggs arent grenades :) As everything before its configurable!
Using Durability, there are now 19 Custom Grenades (by default its clayball starting with Durability 25560 ending with 25579)
Easy Commands to spawn these Durability Grenades
I suggest to use RecipeManager to give your users a way to craft the new Durability Grenades :)
Eggs and Snowballs are using Durability "25565". Customgrenades are starting with 25560 (effect: speed) and ending with 25579 (effect: poison).
You need to give the permissions. (isnt really an caveat, is it?)
May not work with other Plugins, which let you throw Snowballs, Eggs, your Custom Grenades or Slimeballs with Left Click.