Was taking a peek in the Item class to get a method, and I noticed this unnamed method.

 

 public float func_150893_a(ItemStack p_150893_1_, Block p_150893_2_){
        return 1.0F;
    }

 

I just updated to the recommended build of 1.7.10

Anyone know what it might do?

If you do a search in that class, you'll see that it's referenced in the getDigSpeed method so it probably has to do with mining speed. If you look at the ItemPickaxe class, you'll see that it overrides the func_150893_a method in ItemTool which overrides that method in the Item class.