And how to reveal it in LuCI, as we all know how carefully people pay attention to the output when they install packages through the GUI.
As an example of potential benefits, package messages would have helped the OP of [Solved] E-mail WAN IP when changed, with 'mailsend'? to know that they needed the provider-specific package to complete their configuration.
Feel free to poke me if this rises to the level of action.