Package mount points

What determines the mount point reported for a package?

On my development machine here, I get

mount

/pkgs/repository/GNU/GNUEmacs/core-21.2-bld8 on / type pkg
/dev/hd0t79 on / type qnx4
/boot/fs/qnxbase.qfs on /pkgs/base type qnx4
etc

On a target installation which has had some of our packages
installed, I get

mount

/pkgs/repository/waukes/htdoc/core-1.0 on / type pkg
/dev/hd0t77 on / type qnx4
saturn:/home on /home type NFSv2
/boot/fs/qnxbase.qfs on /pkgs/base type qnx4

In both of these there is a package installed at /
But not all packages do this - there are several of
our packages on the second machine, but only one
shows up in the mount list.

So what in the package definition causes this.

Hope someone can help
William Morris