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Oracle: SYS_ROW_ETAG

For all practical purposes, sys_row_etag(col_1[, col_2 … ]) seems to calculate a hash value from the values of the passed column values, where the order of the columns doesn't play a role. 
drop table if exists tq84_etag_test_1;
drop table if exists tq84_etag_test_2;
drop table if exists tq84_etag_test_3;

create table tq84_etag_test_1 (
   num number,
   txt varchar2(10)
);

insert into tq84_etag_test_1 values
   (1, 'one'  ),
   (2, 'two'  ),
   (3, 'three');

create table tq84_etag_test_2       as select * from tq84_etag_test_1;
create table tq84_etag_test_3(n, t) as select * from tq84_etag_test_1;

select sys_row_etag(num) etag_num, sys_row_etag(txt) etag_txt, sys_row_etag(num, txt) etag_num_txt, sys_row_etag(txt, num) etag_txt_num from tq84_etag_test_1 where num = 2 union all
select sys_row_etag(num) etag_num, sys_row_etag(txt) etag_txt, sys_row_etag(num, txt) etag_num_txt, sys_row_etag(txt, num) etag_txt_num from tq84_etag_test_2 where num = 2 union all
select sys_row_etag(n  ) etag_num, sys_row_etag(t  ) etag_txt, sys_row_etag(n  , t  ) etag_num_txt, sys_row_etag(t  , n  ) etag_txt_num from tq84_etag_test_3 where n   = 2;

update tq84_etag_test_1 set txt = 'TWO' where num = 2;
update tq84_etag_test_2 set txt = 'TWO' where num = 2;
update tq84_etag_test_3 set t   = 'TWO' where n   = 2;

select sys_row_etag(num) etag_num, sys_row_etag(txt) etag_txt, sys_row_etag(num, txt) etag_num_txt, sys_row_etag(txt, num) etag_txt_num from tq84_etag_test_1 where num = 2 union all
select sys_row_etag(num) etag_num, sys_row_etag(txt) etag_txt, sys_row_etag(num, txt) etag_num_txt, sys_row_etag(txt, num) etag_txt_num from tq84_etag_test_2 where num = 2 union all
select sys_row_etag(n  ) etag_num, sys_row_etag(t  ) etag_txt, sys_row_etag(n  , t  ) etag_num_txt, sys_row_etag(t  , n  ) etag_txt_num from tq84_etag_test_3 where n   = 2;

update tq84_etag_test_1 set txt = 'two' where num = 2;
update tq84_etag_test_2 set txt = 'two' where num = 2;
update tq84_etag_test_3 set t   = 'two' where n   = 2;

select sys_row_etag(num) etag_num, sys_row_etag(txt) etag_txt, sys_row_etag(num, txt) etag_num_txt, sys_row_etag(txt, num) etag_txt_num from tq84_etag_test_1 where num = 2 union all
select sys_row_etag(num) etag_num, sys_row_etag(txt) etag_txt, sys_row_etag(num, txt) etag_num_txt, sys_row_etag(txt, num) etag_txt_num from tq84_etag_test_2 where num = 2 union all
select sys_row_etag(n  ) etag_num, sys_row_etag(t  ) etag_txt, sys_row_etag(n  , t  ) etag_num_txt, sys_row_etag(t  , n  ) etag_txt_num from tq84_etag_test_3 where n   = 2;

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