/vip-config directory
The /vip-config directory contains a file named vip-config.php. This is where to put things usually found in wp-config.php. Not all settings can be changed, as VIP has optimized certain aspects of the WordPress install, but this file is useful for defining an API key or secret or issue a very early redirect.
Most of WordPress is not available when this file is loaded. The inclusion of WordPress functions or plugin defined functions will most likely result in a fatal error for an undefined function. Code in this file should be limited to pure PHP.
Caution
Changes to vip-config.php should be tested in a non-production environment before deploying to production.
It is likely for fatal errors or syntax errors in this file to make an entire site or multisite unavailable.