Inconsistent "ICU Locale" output on older server versions

Re: To Peter Eisentraut
> This hardly fits in normal-size terminals:
>
> =# \l
> List of databases
> Name │ Owner │ Encoding │ Collate │ Ctype │ ICU Locale │ Locale Provider │ Access privileges
> ───────────┼───────┼──────────┼────────────┼────────────┼────────────┼─────────────────┼───────────────────
> postgres │ myon │ UTF8 │ de_DE.utf8 │ de_DE.utf8 │ │ libc │
> template0 │ myon │ UTF8 │ de_DE.utf8 │ de_DE.utf8 │ │ libc │ =c/myon ↵
> │ │ │ │ │ │ │ myon=CTc/myon
> template1 │ myon │ UTF8 │ de_DE.utf8 │ de_DE.utf8 │ │ libc │ =c/myon ↵
> │ │ │ │ │ │ │ myon=CTc/myon
> (3 rows)

Another gripe here: The above is the output when run against a PG15
cluster, created without an ICU locale set.

When running psql 15 against PG 14, the output is this:

$ psql -l
List of databases
Name │ Owner │ Encoding │ Collate │ Ctype │ ICU Locale │ Locale Provider │ Access privileges
───────────┼──────────┼──────────┼────────────┼────────────┼────────────┼─────────────────┼───────────────────────
postgres │ postgres │ UTF8 │ de_DE.utf8 │ de_DE.utf8 │ de_DE.utf8 │ libc │
template0 │ postgres │ UTF8 │ de_DE.utf8 │ de_DE.utf8 │ de_DE.utf8 │ libc │ =c/postgres ↵
│ │ │ │ │ │ │ postgres=CTc/postgres
template1 │ postgres │ UTF8 │ de_DE.utf8 │ de_DE.utf8 │ de_DE.utf8 │ libc │ =c/postgres ↵
│ │ │ │ │ │ │ postgres=CTc/postgres
(3 rows)

The "ICU Locale" column is now populated, that seems wrong.

The problem is in the else branch in src/bin/psql/describe.c around
line 900:

+ if (pset.sversion >= 150000)
+ appendPQExpBuffer(&buf,
+ " d.daticulocale as \"%s\",\n"
+ " CASE d.datlocprovider WHEN 'c' THEN 'libc' WHEN 'i' THEN 'icu' END AS \"%s\",\
+ gettext_noop("ICU Locale"),
+ gettext_noop("Locale Provider"));
+ else
+ appendPQExpBuffer(&buf,
+ " d.datcollate as \"%s\",\n" <--- there
+ " 'libc' AS \"%s\",\n",
+ gettext_noop("ICU Locale"),
+ gettext_noop("Locale Provider"));

I'd think this should rather be

+ " '' as \"%s\",\n"

Christoph