The last tab in the Backblaze settings contains several useful reports related to the Backblaze backups.
The first report displayed is a summary of the types of files that are included in the backup. Any files that does not meet any of the first 8 categories is included in the "Other" section.
The second report, "Files Scheduled for Backup", shows the files currently in queue to be uploaded. If a backup is in progress or paused, the full path of each file awaiting upload will be shown. If the backup is up to date, no files will appear in the list.
The last report in the Backblaze settings is the "Files With Issues" report. If a file is unable to be backed up, it will be listed with the cause. If you notice that there are a number of files that do not appear to be uploading, checking this report is a good reference to start with.