Explain output difference in rows column

+------+-------------+-------+------+---------------+------+---------+------+------+-------------------+

| id   | select_type | table | type | possible_keys | key  | key_len | ref  | rows | Extra             |

+------+-------------+-------+------+---------------+------+---------+------+------+-------------------+

|    1 | SIMPLE      | NULL  | NULL | NULL          | NULL | NULL    | NULL | 8    | Deleting all rows |

+------+-------------+-------+------+---------------+------+---------+------+------+-------------------+

+------+-------------+-------+------+---------------+------+---------+------+------+-------------------+

| id   | select_type | table | type | possible_keys | key  | key_len | ref  | rows | Extra             |

+------+-------------+-------+------+---------------+------+---------+------+------+-------------------+

|    1 | SIMPLE      | NULL  | NULL | NULL          | NULL | NULL    | NULL | 1    | Deleting all rows |

+------+-------------+-------+------+---------------+------+---------+------+------+-------------------+

set optimizer_record_context=ON;

create table t1 (c1 integer, c2 integer, c3 integer);

insert into t1 values

  (1,1,1), (1,2,2), (1,3,3), (2,1,4), (2,2,5), (2,3,6), (2,4,7), (2,5,8);

create temporary table t select * from t1;

explain delete from t1 order by c2;

SELECT context INTO DUMPFILE 'context1.txt' FROM INFORMATION_SCHEMA.OPTIMIZER_CONTEXT;

source context1.txt