-> % heroku help plugins
Usage: heroku plugins
Lists installed plugins
--core # show core plugins
Example:
$ heroku plugins
Additional commands, type "heroku help COMMAND" for more details:
plugins:install URL # install a plugin
plugins:link [PATH] # This is useful when developing plugins locally.
plugins:uninstall PLUGIN # uninstall a plugin
plugins:update [PLUGIN] # updates all plugins or a single plugin by name