Regions Override, available from the upper right corner of your admin panel on all page types or under Edit » Additional Options » Page Layout panel, gives you the ability to strip out pre-configured page regions on a page-by-page basis. Removing certain regions can be beneficial especially if using Layout Builder or wishing to take advantage of all available space when presenting output from a View, all without having to implement any subtheming to achieve the same effect.

Understanding Layout Builder's configuration and structure is key to learning what's available and how to use this feature.

Now, let's identify Layout Builder's sections and their purpose.