oont-contents/plugins/jetpack-boost/app/modules/optimizations/page-cache/pre-wordpress

Pre_WordPress namespace

Everything in this directory / namespace contains code which can execute before WordPress is fully initialized. It can be called from advanced-cache.php, but it can also be called directly from the main Boost code-base.

Nothing in the Pre_WordPress namespace may rely on autolaoding to load things; you must include an explicit require_once instruction in the entrypoint file Boost_Cache.php. It also must not rely on any WordPress functionality that is unavailable at the time that advanced-cache.php is executed.

You can use this code from elsewhere in Boost, and you can autoload it from outside this namespace, though.