Controls whether or not to use the international form of the State field. If set to true, state field will become a select menu with a list of US state abbreviations. Use pmpro_states to modify the array of state abbreviations used.

apply_filters("pmpro_state_dropdowns", false);

Parameters

bool (false)

Source

File: https://github.com/strangerstudios/paid-memberships-pro/blob/master/pages/checkout.php