You can now see a breakdown of the taxes and fees on offers and orders

Offers and orders now include a tax_breakdown: the airline's itemisation of tax_amount by tax code. Each line gives the tax code, the amount and currency the airline quoted it in, a short name and a fuller description of the charge, and carrier_imposed, which tells you whether it is a government or airport tax or a fee the airline sets itself, such as a fuel surcharge. You can use it to show travellers what makes up the price, to itemise taxes on invoices, and to answer questions about a specific charge.

The breakdown is returned when you retrieve, price or upsell a single offer, and on the order you create from it. It stays up to date as the order's price changes: when you change the order, add services to it or pay for a held order at a new price, the breakdown is replaced with the airline's itemisation of the new tax_amount. It is not included in search results, and orders created before this launch return an empty list.

The API reference has the full field description, including how to treat an empty list and lines quoted in a currency other than your billing currency.