In this section, we take note of some of the tools that provide services to a Plone site.
Components that provide global services to a Plone site are implemented as tools. They can be looked up by name (e.g. getToolByName(context, "portal_actions") from a Python script). A tool covers a specific area of functionality. Plone uses a number of tools from the CMF, extending them, and products may provide tools of their own. Tools range from the complex to the simplistic.
They may provide a ZMI configuration point for a list of static properties, such as portal_actionicons, or they may form the backbone of a Plone site, like portal_actions. Tools may be interdependent, and use other tools: the portal_actions tool acquires actions from all the tools it is configured to regard as action providers, and forms a central point for the rest of Plone to look for actions.
Some tools have only a stub in the ZMI. plone_utils has no ZMI page at all, but provides some utility functions for use from Python scripts.
Other tools may be extensively configured via the ZMI and provide browseable documentation. portal_form_controller is one such. The portal_workflow ZMI interface doesn't provide much in the way of documentation, but can it exposes all aspects of workflow definition.