Everything beyond the basics lives in plugins: markup by category, value replacements, image processing, exports, meta tags. This section covers only the general arrangement; each plugin will get its own page with settings and a demonstration.
Plugins
How to switch a plugin on, and how the format works if you decide to write your own.
Switching a plugin on
A folder in custom/Plugins, then a toggle in Settings → Plugins and the order of application.Writing your own plugin
What a plugin gets from the core and where it can step in. Short, for those who intend to write one.Related on the site