TYPO3 Core

\TYPO3\CMS\Core\DataHandling\DataHandler->checkValue()

// Getting config for the field
$tcaFieldConf = $GLOBALS['TCA'][$table]['columns'][$field]['config'];

e.g.
$table = 'example'
$filed = 'title'

'title' is an input field in 'example'. If I use 'example' as an inline element where 'title' should be used as a text field with RTE the 'overrideChildTca' is not used.

TCA title field (normal use)

...
'title' => [
            'config' => [
                'type' => 'input',
                'size' => 60,
                'eval' => 'required',
            ]
        ],
...

TCA title field (as part of an inline element)

            ...
            'config' => [
                'overrideChildTca' => [
                    'columns' => [
                        'title' => [
                            'config' => [
                                'type' => 'text',
                                'enableRichtext' => true,
                                'richtextConfiguration' => 'myrteconfig',
                            ]
                        ]
                    ]
                ]
            ]
        ]
...

(For me it is an issue because I want to use a transformation service
$GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['t3lib/class.t3lib_parsehtml_proc.php']['transformation']['tx_my_transformation'] = Me\My\Service\RteTransformationService';)