This window shows the keyboard commands that are currently active, arranged by window type. Some shortcuts are global (they are always available irrespective of context), and some are only available when a particular window type is active. Shortcuts are not available when text is being edited.
Shortcut editing works the same way as in the Gimp. Select the shortcut in the list, then click on the text in the Shortcut column. Currently, saving of edited shortcuts is not yet implemented, so changes will be lost when the gui is closed.