Open the Festivals Tab, and display the list corresponding to the year for which you wish to export the holidays.
Next, press the Export icon in the toolbar at the bottom of the screen:
You will be prompted to choose to which Calendar to export the holidays of the year, as displayed on screen. You can pick any Calendar defined in your iOS system.
NB: All the events listed on this screen will be transfered — and only these ones.
This means that, if you chose (Settings screen) to show your user-defined anniversaries in the Festivals list, they will be transfered too. It also means that only the secular dates shown on the screen (i.e. for the selected year) are transfered. If you need to transfer additional years, you may browse to a different year and repeat the Export operation.