We had a great question come up internally here at Sugar last week:
Is it possible to put custom smarty plugins in custom/include/Smarty/plugins/ and have smarty pick them up or do they need to be in include/Smarty/plugins/?
The answer here is yes! This was a new feature added in Sugar 6.3 and came from our Professional Services team, where Smarty will look for available plugins first in the custom/include/Smarty/plugins directory if it exists, and then in include/Smarty/plugins/. This allows you to not only add new Smarty plugins, but also customize the behavior of the existing ones that ship with Sugar by creating one’s in the custom directory with the same name. Learn more about authoring plugins in the official Smarty documentation.