This package includes"libz"

-rwxr-xr-x-     root     root      70704 Jul 24 08:32 /usr/X11R6/lib/libz.a
lrwxrwxrwx-     root     root         13 Jul 24 08:32 /usr/X11R6/lib/libz.so -> libz.so.1.1.2
-rwxr-xr-x-     root     root      61073 Jul 24 08:32 /usr/X11R6/lib/libz.so.1.1.2
drwxr-xr-x-     root     root       1024 Jul 24 08:32 /usr/doc/packages/libz
-rw-r--r---     root     root      20841 Mar 19 11:56 /usr/doc/packages/libz/ChangeLog
-rw-r--r---     root     root       7085 Mar 19 15:46 /usr/doc/packages/libz/README
-rw-r--r---     root     root       9656 Jan 19 18:21 /usr/doc/packages/libz/algorithm.txt
-rw-r--r---     root     root       7157 Jul 24 08:32 /usr/include/zconf.h
-rw-r--r---     root     root      40735 Jul 24 08:32 /usr/include/zlib.h
-rwxr-xr-x-     root     root      70704 Jul 24 08:32 /usr/lib/libgz.a
lrwxrwxrwx-     root     root         14 Jul 24 08:32 /usr/lib/libgz.so -> libgz.so.1.1.2
-rwxr-xr-x-     root     root      61073 Jul 24 08:32 /usr/lib/libgz.so.1.1.2
-rwxr-xr-x-     root     root       1668 Jul 24 08:32 /usr/man/man3/zlib.3.gz