Maintain an inventory (incl. SaaS) and map data flows.
What good looks like — maturity levels
This is a foundational area — relevant to organizations of every size.
Basic
Asset list
Standard
Maintained inventory incl. SaaS
Formal
CMDB + data-flow map (automated discovery)
This library is general education, not advice about your specific organization. It describes what each control is and what strong practice looks like; whether and how any of it applies to you is your decision, in consultation with your carrier, broker, or counsel.