Set custom application for file comparison in caja

How can I set custom application which is being invoked when I press "Differences" button in "File Conflict" dialog? I did not find corresponding option in "File Management Preferences". I did not find it using "dconf Editor" in org.mate.caja.*. I did not find it in files located at /usr/share/caja and ~/.config/caja. Where is this option being stored at?