While looking for a reason 'Xorg-7.7-lib.tcz.list' is not available, discovered that this extension is just empty with only one directory.
Is this just a 'placeholder' extension to load dependencies?
$ sudo unsquashfs Xorg-7.7-lib.tcz
Parallel unsquashfs: Using 1 processor
0 inodes (0 blocks) to write
created 0 files
created 2 directories
created 0 symlinks
created 0 devices
created 0 fifos
$ cd squashfs-root/
$ tree
.
`-- usr
1 directory, 0 files
The list of dependencies is a bit long...
cat Xorg-7.7-lib.tcz.dep
libFS.tcz
libXaw.tcz
libXcomposite.tcz
libXcursor.tcz
libXdamage.tcz
libXfont2.tcz
libXft.tcz
libXinerama.tcz
libXrandr.tcz
libXres.tcz
libXss.tcz
libXtst.tcz
libXvmc.tcz
libXxf86dga.tcz
libXxf86vm.tcz
libxkbfile.tcz