src/Forms/GridField/SEOEditorMetaDescriptionColumn.php
public function getColumnContent($gridField, $record, $columnName)
    {
        $field = new TextareaField('MetaDescription');
        $value = $gridField->getDataFieldValue($record, $columnName);
        $value = $this->formatValue($gridField, $record, $columnName, $value);
        $field->setName($this->getFieldName($field->getName(), $gridField, $record));
        $field->setValue($value);
        $field->setAttribute('data-name', 'MetaDescription');

        return $field->Field() . $this->getErrorMessages();
    }
public function getColumnContent($gridField, $record, $columnName)
    {
        $field = new TextareaField('MetaDescription');
        $value = $gridField->getDataFieldValue($record, $columnName);
        $value = $this->formatValue($gridField, $record, $columnName, $value);
        $field->setName($this->getFieldName($field->getName(), $gridField, $record));
        $field->setValue($value);
        $field->setAttribute('data-name', 'MetaDescription');

        return $field->Field() . $this->getErrorMessages();
    }
HTML for the column, content of the <td> element.

@param  GridField $gridField
@param  DataObject $record - Record displayed in this row
@param  string $columnName
@return string - HTML for the column. Return NULL to skip.