'COVERED IN ANOTHER PLAN' field in Benefits Summary is related to what field in Eligibility Profiles

We have a requirement to build an Eligibility Profile for employee based on if the employee has a Specific Plan eligibility initially required by the government, which will enable the employee is eligible for a Plan configured in system. Can't seem to find where 'COVERED IN ANOTHER PLAN' in Benefits Summary related to Eligibility Profiles and, where this flag is updated for an employee in Person Management for "OPTED FOR MEDICARE" field in eligibility profile.