core-bundle/src/Resources/contao/dca/tl_module.php
public function getLayoutSections()
	{
		$arrSections = array('header', 'left', 'right', 'main', 'footer');

		// Check for custom layout sections
		$objLayout = $this->Database->query("SELECT sections FROM tl_layout WHERE sections!=''");

		while ($objLayout->next())
		{
			$arrCustom = Contao\StringUtil::deserialize($objLayout->sections);

			// Add the custom layout sections
			if (!empty($arrCustom) && \is_array($arrCustom))
			{
				foreach ($arrCustom as $v)
				{
					if (!empty($v['id']))
					{
						$arrSections[] = $v['id'];
					}
				}
			}
		}

		return Contao\Backend::convertLayoutSectionIdsToAssociativeArray($arrSections);
	}
public function getLayoutSections()
	{
		$arrSections = array('header', 'left', 'right', 'main', 'footer');

		// Check for custom layout sections
		$objLayout = $this->Database->query("SELECT sections FROM tl_layout WHERE sections!=''");

		while ($objLayout->next())
		{
			$arrCustom = Contao\StringUtil::deserialize($objLayout->sections);

			// Add the custom layout sections
			if (!empty($arrCustom) && \is_array($arrCustom))
			{
				foreach ($arrCustom as $v)
				{
					if (!empty($v['id']))
					{
						$arrSections[] = $v['id'];
					}
				}
			}
		}

		return Contao\Backend::convertLayoutSectionIdsToAssociativeArray($arrSections);
	}
Return all layout sections as array

@return array