anchor.diff:  
   (define-class history-entry ()
     ((url (quri:uri "")
  -        :type quri:uri)
  +        :type (or quri:uri string))
      (title "")
      (id ""
          :documentation "The `id' of the buffer that this entry belongs to the branch of.")
      (last-access (local-time:now)
  -                :type local-time:timestamp)
  +                :type (or local-time:timestamp string))
      ;; TODO: For now we never increment the explicit-visits count.  Maybe we
      ;; could use a new buffer slot to signal that the last load came from an
      ;; explicit request?
  
positive.code:                   ;; Switch to the last active buffer.
                    (when (htree:current history)
                      (switch-buffer
                       :id (id (htree:data (htree:current history)))))))
                (setf (get-data path) history))
               (hash-table
                (echo "Importing deprecated global history of ~a URLs from ~s."
                      (hash-table-count history)
  
negative.code:               (echo "Loading history of ~a URLs from ~s."
                      (htree:size history)
                      (expand-path path))
                (setf (get-data path) history)
                (when restore-session-p
                  (sera:and-let* ((buffer-histories (buffer-local-histories-table history)))
                    ;; Make the new buffers.
  