app/code/community/Aoe/TemplateHints/Model/Adminhtml/System/Config/Source/HintRenderer.php
public function toOptionArray() {
        $options = array();
        $options[] = array(
            'value'=> 'aoe_templatehints/renderer_comment',
            'label'=> Mage::helper('aoe_templatehints')->__('Comments')
        );
        $options[] = array(
            'value'=> 'aoe_templatehints/renderer_opentip',
            'label'=> Mage::helper('aoe_templatehints')->__('Popups')
        );
        $options[] = array(
            'value'=> 'aoe_templatehints/renderer_tipOnly',
            'label'=> Mage::helper('aoe_templatehints')->__('Popups (border initially invisible)')
        );

        Mage::dispatchEvent('aoetemplatehints_hintrenderer_options', array('options' => &$options));

        return $options;
    }
public function toOptionArray() {
        $options = array();
        $options[] = array(
            'value'=> 'aoe_templatehints/renderer_comment',
            'label'=> Mage::helper('aoe_templatehints')->__('Comments')
        );
        $options[] = array(
            'value'=> 'aoe_templatehints/renderer_opentip',
            'label'=> Mage::helper('aoe_templatehints')->__('Popups')
        );
        $options[] = array(
            'value'=> 'aoe_templatehints/renderer_tipOnly',
            'label'=> Mage::helper('aoe_templatehints')->__('Popups (border initially invisible)')
        );

        Mage::dispatchEvent('aoetemplatehints_hintrenderer_options', array('options' => &$options));

        return $options;
    }
Get option array

@return array