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
anexplicit   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_ctypelocale, 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