Hi Alex,
You don’t actually need to download it, as you have the original in Magento, you just need to copy it to the app/code/local/Mage/Core folder and make the adjustments.
Step 1: Deactivate the __() function in Magento
Step 1, is not to install a plugin, we need to prep our environment first. To do this we copy ‘~/your-magento/app/code/core/Mage/Core/functions.php’ into ‘~/your-magento/app/code/local/Mage/Core/functions.php’ and find code for the function __() (around line 90)
function __() { return Mage::app()->getTranslator()->translate(func_get_args()); }
We will replace that code with the following
if(!function_exists('__')) { function __() { return Mage::app()->getTranslator()->translate(func_get_args()); } }