rpress_get_payment_tax

The rpress_get_payment_tax filter is used to get the payment tax, the filter includes a three-parameter.
$this->tax is gets all taxes.
$this->ID is gets the id.

An example of how you can append additional information:

function get_payment_tax($tax){
$tax = //return tax rate.
}
add_filter( 'rpress_get_payment_tax', 'get_payment_tax', 10 , 2);