src/Configuration/PropertyConfigPass.php
private function getFieldFormat($fieldType, array $backendConfig)
    {
        if (\in_array($fieldType, ['date', 'date_immutable', 'dateinterval', 'time', 'time_immutable', 'datetime', 'datetime_immutable', 'datetimetz'])) {
            // make 'datetimetz' use the same format as 'datetime'
            $fieldType = ('datetimetz' === $fieldType) ? 'datetime' : $fieldType;
            $fieldType = ('_immutable' === \mb_substr($fieldType, -10)) ? \mb_substr($fieldType, 0, -10) : $fieldType;

            return $backendConfig['formats'][$fieldType];
        }

        if (\in_array($fieldType, ['bigint', 'integer', 'smallint', 'decimal', 'float'])) {
            return isset($backendConfig['formats']['number']) ? $backendConfig['formats']['number'] : null;
        }
    }
private function getFieldFormat($fieldType, array $backendConfig)
    {
        if (\in_array($fieldType, ['date', 'date_immutable', 'dateinterval', 'time', 'time_immutable', 'datetime', 'datetime_immutable', 'datetimetz'])) {
            // make 'datetimetz' use the same format as 'datetime'
            $fieldType = ('datetimetz' === $fieldType) ? 'datetime' : $fieldType;
            $fieldType = ('_immutable' === \mb_substr($fieldType, -10)) ? \mb_substr($fieldType, 0, -10) : $fieldType;

            return $backendConfig['formats'][$fieldType];
        }

        if (\in_array($fieldType, ['bigint', 'integer', 'smallint', 'decimal', 'float'])) {
            return isset($backendConfig['formats']['number']) ? $backendConfig['formats']['number'] : null;
        }
    }
Returns the date/time/datetime/number format for the given field
according to its type and the default formats defined for the backend.

@param string $fieldType
@param array  $backendConfig

@return string The format that should be applied to the field value