timeshift.keepforMinutes
The amount of time (in minutes) before each time-shift file is deleted.
Setting the value to -1 means the time-shift file will not be deleted.
A value = 0 means immediate deletion. If the file cannot be deleted because it's still in use, it will be added to the Auto-Deletable File List.
Setting to a value > 0 gives time for the time-shift file to be renamed or copied before it is deleted.