core-bundle/src/Resources/contao/library/Contao/Session.php
public function remove($strKey)
	{
		// Map the referer (see #281)
		if (\in_array($strKey, $this->mappedKeys))
		{
			$this->session->remove($strKey);
		}
		else
		{
			$this->sessionBag->remove($strKey);
		}
	}
public function remove($strKey)
	{
		// Map the referer (see #281)
		if (\in_array($strKey, $this->mappedKeys))
		{
			$this->session->remove($strKey);
		}
		else
		{
			$this->sessionBag->remove($strKey);
		}
	}
Remove a session variable

@param string $strKey The variable name