Invalid Unicode escape value at or near "\u0000"

Hi, hackers

When I try to insert an Unicode "\u0000", there is an error $subject.

postgres=# CREATE TABLE tbl (s varchar(10));
CREATE TABLE
postgres=# INSERT INTO tbl VALUES (E'\u0000');
ERROR: invalid Unicode escape value at or near "\u0000"
LINE 1: INSERT INTO tbl VALUES (E'\u0000');
^

"\u0000" is valid unicode [1], why not we cannot insert it?

[1] https://www.unicode.org/charts/PDF/U0000.pdf

--
Regrads,
Japin Li.
ChengDu WenWu Information Technology Co.,Ltd.