Feature: #64386 - Public Content Object Registration

See forge#64386


A new global option is now available to register and/or extend/overwrite content objects like TEXT. A list of all available Content Objects that was previously registered within the main ContentObjectRenderer class is now moved to the global array $GLOBALS['TYPO3_CONF_VARS']['FE']['ContentObjects'] which allows for modifications via third-party extensions.

Example: Register a new Content Object EXAMPLE in a third-party extension

$GLOBALS['TYPO3_CONF_VARS']['FE']['ContentObjects']['EXAMPLE'] = Acme\MyExtension\ContentObject\ExampleContentObject::class

The registered class must be a subclass of TYPO3\CMS\Frontend\ContentObject\AbstractContentObject.

For future autoloading mechanisms, it is encouraged to place the custom ContentObject class inside EXT:myextension/Classes/ContentObject/.