Other postemployment benefits (or OPEB) is an accounting concept created by the Governmental Accounting Standards Board (GASB) by pronouncements designed to address expenses that entities may or may not be legally bound to pay, but pay as a moral obligation.
The applicable GASB statements are:
GASB pronouncements apply to governmental entities, public benefit entities, public employee retirement systems, and public utilities, hospitals and other healthcare providers, and colleges and universities.
References
Other postemployment benefits Wikipedia(Text) CC BY-SA