Composes the stack banner from explicit versions, so a surface attached to a daemon writes out the daemon's stack rather than its own install's.
Versions keyed by short package name; a package with no version (an older daemon that did not report it) gets no row.
The served web surface's version, or null for no row.
One name version line per package known, in stack order.
name version
Composes the stack banner from explicit versions, so a surface attached to a daemon writes out the daemon's stack rather than its own install's.