Why are data from more than 30 days ago displayed on the backup details screen?

The backup function allows you to go back to a state up to 30 days in the past.
For the following reason, backup data from more than 30 days ago may be displayed:

If no edits have been made for a long period since the last backup was taken and
the "state at the time of backup" = "state from 30 days before the restoration operation,"
restoration is possible even if the backup date is more than 30 days ago.

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