This needs to be enhanced - describe how the SummaryPanel is customized by summaryKey attributes of user input fields and give an example

The SummaryPanel gives a summary of all shown panels. The best place for it is just in front of the InstallPanel.

Normally it contains a warning that this is the last panel before installation. The panel contains a scrollable HTML text area to display the summary. The information displayed is collected from each panel by calling the methods getSummaryCaption and getSummaryBody. The method getSummaryCaption is implemented in IzPanel with a panel name default text, getSummaryBody has to be implemented in all panels which should be presented in the summary. If the secound method is not implemented, no summary of this panel will be shown.

Additional it is possible to log the contents of the summary panel into a HTML file.

Since IzPack 5.1.3, the SummaryPanel Next button text can be overridden by modifying the txt value for the following key in your translation xml <str id="" txt="Next"/>