How do I specify an addon that is not a dependency of my package?
You can include a slack-suggests file within your packages ./install/ directory. The format of this file follows the slack-required, except version information is to be left out. This version information is useless as you are just making a suggestion, not a requirement. If there is a required version of a package you can either specify it within ./install/slack-required or include it within the documentation inside of your package. The suggestion information is presented during the transaction report or via the –show pkg-name query.