Where would all the possible service improvement opportunities be recorded?

The CSI register is a formal document maintained within ITIL's Continual Service Improvement lifecycle stage, used to record every improvement opportunity identified regardless of size, source, or current status. It captures details such as description, priority, business benefit, and owner, ensuring that all improvement initiatives are visible, tracked, and managed in a structured way.

The Known Error Database stores records of known errors and their workarounds or fixes identified during Problem Management, not service improvement opportunities.

The Capacity Management Information System stores capacity and performance data used for capacity planning, trending, and reporting - not improvement opportunities.

The Configuration Management Database stores details about configuration items and their relationships, not service improvement opportunities.