As the name implies, the Kinds of Operations Equipment List (KOEL) is a list of equipment installed in an aircraft that specifies for which kinds of operations a specific piece of equipment is required. The KOEL is used as part of the process of determining if an aircraft with inoperative equipment is airworthy. The KOEL is typically published by the aircraft manufacturer as part of the Limitations section of the Airplane Flight Manual (AFM) or Pilot's Operating Handbook (POH).
For example, a KOEL may state that a particular backup instrument must be working to fly under Day IFR or Night IFR, but is not required for Day VFR or Night VFR. In many ways similar to a Minimum Equipment List, there may be specific guidance to operating the aircraft without that piece of equipment.
You are planning to operate a Cessna 172S on a night VFR flight. You arrive to the airplane and discover that the Standby Altimeter was written up, deactivated, and placarded "INOP" earlier in the day. Based upon the KOEL, can the aircraft still be operated legally?