default_text_search_config

When I run initdb -E EUC_JP --no-locale, I found following in my
postgresql.conf:

default_text_search_config = 'pg_catalog.english'

The manual says:

default_text_search_config (string)

Selects the text search configuration that is used by those
variants of the text search functions that do not have an explicit
argument specifying the configuration. See Chapter 12 for further
information. The built-in default is pg_catalog.simple, but initdb
will initialize the configuration file with a setting that
corresponds to the chosen lc_ctype locale, if a configuration
matching that locale can be identified.

So I thought the initial value for it should be pg_catalog.simple,
rather than pg_catalog.english. If this is not a bug, what is the
idea behind lc_ctype = C corresponds to 'pg_catalog.english'?
When is pg_catalog.simple supposed to be used?
--
Tatsuo Ishii
SRA OSS, Inc. Japan