Operator ~<~ in Postgres - postgresql

Question

(Originally part of this question, but it was bit irrelevant, so I decided to make it a question of its own.)
I cannot find what the operator ~<~ is. The Postgres manual only mentions ~ and similar operators here, but no sign of ~<~.
When fiddling in the psql console, I found out that these commands give the same results:
SELECT * FROM test ORDER BY name USING ~<~;
SELECT * FROM test ORDER BY name COLLATE "C";
And these gives the reverse ordering:
SELECT * FROM test ORDER BY name USING ~>~;
SELECT * FROM test ORDER BY name COLLATE "C" DESC;
Also some info on the tilde operators:
\do ~*~
List of operators
Schema | Name | Left arg type | Right arg type | Result type | Description
------------+------+---------------+----------------+-------------+-------------------------
pg_catalog | ~<=~ | character | character | boolean | less than or equal
pg_catalog | ~<=~ | text | text | boolean | less than or equal
pg_catalog | ~<~ | character | character | boolean | less than
pg_catalog | ~<~ | text | text | boolean | less than
pg_catalog | ~>=~ | character | character | boolean | greater than or equal
pg_catalog | ~>=~ | text | text | boolean | greater than or equal
pg_catalog | ~>~ | character | character | boolean | greater than
pg_catalog | ~>~ | text | text | boolean | greater than
pg_catalog | ~~ | bytea | bytea | boolean | matches LIKE expression
pg_catalog | ~~ | character | text | boolean | matches LIKE expression
pg_catalog | ~~ | name | text | boolean | matches LIKE expression
pg_catalog | ~~ | text | text | boolean | matches LIKE expression
(12 rows)
The 3rd and 4th rows is the operator I'm looking for, but the description is a bit insufficient for me.

Answer 1

~>=~, ~<=~, ~>~ and ~<~ are text pattern (or varchar, basically the same) operators, the counterparts of their respective siblings >=, <=, >and <. They sort character data strictly by their byte values, ignoring rules of any collation setting (as opposed to their siblings). This makes them faster, but also invalid for most languages / countries.
The "C" locale is effectively the same as no locale, meaning no collation rules. That explains why ORDER BY name USING ~<~ and ORDER BY name COLLATE "C" end up doing the same. The latter syntax variant should be preferred: more standard, less error-prone.
Detailed explanation in the last chapter of this related answer on dba.SE:
Pattern matching with LIKE, SIMILAR TO or regular expressions in PostgreSQL
Note that ~~ / ~~* are Postgres operators for LIKE / ILIKE and barely related to the above. Similarly, !~~ / !~~* for NOT LIKE / NOT IILKE. (Use standard LIKE notation instead of these "internal" operators.)
Related:
~~ Operator In Postgres
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Find rows where text array contains value similar to input