Every module.json already declares a why for each port under listens,
but plan only ever used it to build the firewall's rule set — nothing
printed it. An operator deciding whether to assign a module had no way
to see what it would open without reading the manifest by hand.
plan <node> now prints each assigned module's listens entries — port,
protocol, source, and its why — right under the module line, so the
same text that feeds the firewall is visible at the point someone is
actually deciding whether to open it.
jschoubben