The Secret treasure of Ehekatl is obtained by having 2525 favor with Ehekatl. To receive it, you must pray. It gives you the feat:
[Race]Quality Stuff are generated around you.
This works with the enchantments of equipment and increases available maximum power of enchantment by 50 (#). Thus, you can have chances to get an equipment that has stronger enchantment power (eg. stronger resistances, etc.). Note that this feat have nothing to do with the type of the enchantments that can be chosen.