Unable to use definition "azure-policy/built-in-policies/policyDefinitions/Key Vault/Secrets_ActivePeriod.json"

When I try to create a policy with the definition from Secrets_ActivePeriod.json I get 4 errors

line 1 "Missing property "policyRule""
line 2 "Property properties is not allowed"
line 51 "Property id is not allowed."
line 52 "Property name is not allowed."

Am I doing something wrong?

Start by opening azure-policy/built-in-policies/policyDefinitions/Key Vault/Secrets_ActivePeriod.json and comparing its structure with the Azure Policy definition format expected by the creation workflow. Use the four reported validation errors as the checklist; done means the definition is accepted without those errors and can be used to create a policy.

Written by the indexing model from the issue text.