Some more details:
The card can replay native DSD, and, as DSD is a bitstream, it's not possible to control volume by software, you cannot multiply or divide a single bit, so it has a software controlled analog volume control for the headphone amp.
The headphone amp is direct coupled to the jack, there is no decoupling resistor or inductor, sothe output impedance is a minute fraction of an ohm.
The GUI allows for setting various digital filter functions for the DAC and ADC, such as regular sync function FIR, or slow rolloff IIR type response.
The AD5056 is swappable, but, before that IC all circuitry is fully balanced using fully differential amplifiers. Similar for the Line In.
The OP275, used for the HPA is swappable.
There is a plot to view in the suite, noise floor is around -155dB. IMD is around -110dB to -120dB depending on op-amp. Harmonics are down to as low as-128dB, again, depending on op-amp - upgrade if you feel the need to get to that kind of level to enjoy music.
The GUI has a graphic EQ.