As with Mail Link, Ribbons logs to %AppData%\SuperOffice folder. It logs to Ribbons.log file by default.
You may also specify the location for the logfile by setting the logpath in SuperOffice.ini.
Please note that logging for Ribbons is only turned on if both these values are set in SuperOffice.ini:
EnableDebug = 1
EnableRibbonLog = 1
Please note running Ribbon vsto file can cause issues and this should not be done. Read more info on the Community forum.