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Jamroom Developers
It depends on what modules you're using. It could be in jrPayment, jrPaypal or jrFoxyCart.
Whichever one its in, if your developer is planning on changing code in any of those modules it will break as soon as an update comes out.
The correct way to adjust something is via
Docs: "Events and Listeners"
https://www.jamroom.net/the-jamroom-network/documentation/module-developer-guide/1011/events-and-listeners
There will be an event in the location that you're after to change whatever you want to from within your own module so no code needs to be changed in the jamroom modules.
That will keep your code safe when things are updated.