DiveIno stores the logbook data in the LOGBOOK.TXT file on the SD card.
If you open one file, its content will be similar to this:
I think it is self explanatory. The files listed in the Dives section refers to the DiveIno log files, which belongs to the individual dives.
The DiveIno file format was changed from plain text to json. Please read the Migrate DiveIno files into json format post for further details!