The configuration file generated by the Firefly III Data Importer (FIDI) is very important. It contains all of your settings and it keeps the authentication information required by Nordigen and Spectre
The configuration file will contain your column roles, mapping and other settings.
Spectre and Nordigen
On top of that the configuration file will contain a reference to your bank, which means you don't need to reauthenticate with your bank.
Use the configuration file with your next import to speed things up. Or use it in a daily cron job.