[Fontconfig] language coverage

[Qianqian Fang]

hi

I downloaded a "Language coverage analyzer" script from

http://dejavu.sourceforge.net/wiki/index.php/Font_utilities

and used it on a CJK font, WenQuanYi Zen Hei to test its
locale coverage. The font file can be downloaded from
http://wenq.org/daily/zenhei/  . After converting ttf file
to sfd using fontforge, and using the latest fc-lang data,
the script produced a table of language coverage. Strangely,
the table indicates there is a 100% coverage to ja language,
however, installing this font to my system and run fc-cache,
then run
  fc-list "WenQuanYi Zen Hei" lang
the output does not include ja (Japanese) language.

I am wondering if fontconfig does additional check to
comparing to fc-lang data, and if there is a way to tell
which code points are missing?

thanks

Qianqian