[gentoo-user] what is /usr/lib64/debug ?

[Allan Gottlieb]

/usr/lib64/debug seems to have in it a duplicate (at least as far as
directory names are concerned) of much of /usr/lib64.

For example

    ajglap lib64 # /bin/pwd
    /usr/lib64/debug/usr/lib64
    ajglap lib64 # du -s * | sort -n | tail -10
    34020       mesa
    53148       gstreamer-0.10
    155992      icedtea6
    161360      llvm
    208932      qt4
    304016      xulrunner-devel-2.0
    308880      xulrunner-2.0
    618408      firefox
    669000      libwebkitgtk-1.0.so.0.7.2.debug
    1087848     libreoffice
    ajglap lib64 # 

Is this correct?  My system is ~amd64

thanks,
allan