Overview
Often when setting up a WordPress site, you need it to run on a bunch of different servers at the same time, such as dev, staging and production, or if switching domains a temporary URL or IP, then the new URL.
WordPress Flexible Configuration is a helper function to set up multiple configurations in an Array format, and have the correct site constants defined automatically, according to the current HTTP_HOST.
The end result is cleaner and tidier than setting up multiple define blocks and if/elses, and also allows to to set common defaults across all configurations.