Whitepapers list more technical specs that your Xperia is capable of, sometimes you can learn a great deal about your device like why your memory is not wholly 32GB or what video codecs your device supports. so here are the Xperia XZ white papers for both versions
Xperia XZ (F8331) white paper
Xperia XZ Dual (F8332) white paper
Xperia™ XZ User guide
