This read-write INTEGER lets an admin specify the desired position a stack unit should occupy in the stack order, though the change only takes effect once rlPhdStackReorder is subsequently triggered. Admins use this when they want to control which unit is treated as first or last in show-list output or unit numbering, for example to keep numbering consistent after physically rearranging units. For example, an admin wanting the newly added unit to become position 1 would write that value here for the relevant unit, then separately trigger rlPhdStackReorder to actually apply the change.