A full list of encodings supported by your Java implementation is now shown in the file system browser's Commands>Encoding menu and other places. Previously only a small list of common encodings was shown.
You can choose which of this list you want to display in the Encodings general options pane.
The encoding used by XML files is (should be?) auto-detected if the file provides an XML declaration like the following:
<?xml version="1.0" encoding="UTF-8"?>