Every time you click 'Save' on the Wiki editing screen, a new version of the Wiki page will be saved to GakuNin RDM. You can view and compare page versions to compare changes.
Click 'Wiki' on the navigation bar of the project's main screen to move to the Wiki editing screen.
When you click the 'Compare' button on the toolbar at the top right of the screen, the 'Compare' pane will be displayed at the right end. *(It will be displayed separately)

Select the version of the Wiki page you wish to compare from the drop-down menus in the 'View' pane and 'Compare' pane.