I've noticed this a value at the end of my configuration.php file in Joomla 3.3.6:
public $asset_id = '1';
What is that for? Maybe a default fallback?
This is not a default variable for Joomla 3.x's (or any other version) configuration.php file. I've done a check to see if this variable is being used anywhere else in Joomla's core. It is, however it's not being called from the configuration.php.
I'm not sure how it got there but the configuration.php should never get changed by any other extensions. The only time it changes or when it should change is when:
I would suggest taking a backup of this file and removing
public $asset_id = '1'; from the production file.