Someone at Atmel is burning through the application note budget to publish Xplain tutorials :-) The information seems to have been previously published in other app notes in a generic form for Xmegas.
AVR1500: Xplain training - XMEGA Basics
AVR1501: Xplain training - XMEGA Timer/Counter
AVR1502: Xplain Training - Direct Memory Access Controller
AVR1503: Xplain training - XMEGA Programmable Multi Interrupt Controller
AVR1504: Xplain training - XMEGA Event System
AVR1505: XMEGA training - ADC
AVR1506: Xplain training - XMEGA clock system
AVR1507: Xplain training - XMEGA Crypto Engines
AVR1508: Xplain training - XMEGA DAC
AVR1509: Xplain training - Low Power
AVR1510: Xplain training - XMEGA USART