Extending templates
You may wish to extend templates for a variety of reasons. For example, a plugin may wish to display extra information after the page footer, or add a new feature to user profiles.
Plugins
Plugins extend themes as part of their main plugin class,
as part of the registerPages()
method.
This is how the Checkin
plugin adds some mapping JavaScript to the HTML page header::
\Idno\Core\Idno::site()->template()->extendTemplate('shell/head','checkin/head');
Themes
Themes have a special way of extending themes as part of their theme.ini file.