Plugins
Create a Plugins folder.
Imagine your want to extend SWMB with a plugin name for example Swel. The directive -plugin (or $PLUGIN) will import your module installed in folder C:\Program File\SWMB\Plugins\SWEL\Modules\ name SWEL.psd1 or Swel.psm1.
The uninstall of SWMB will kept the plugin folder as-is.