The defaults object embedded in your account's Stripe Tax settings.
Reachable from LatticeStripe.Tax.Settings.t/0. These values apply to calculations
that do not override them — notably tax_behavior, which decides whether your prices
are treated as tax-inclusive or tax-exclusive.
Embedded value struct: fields are additive. Keys Stripe adds later appear under
:extra rather than being dropped, so a new field never breaks decoding.