MediaWiki:Api-help-datatype-expiry
Expiry values may be relative (e.g. 5 months or 2 weeks) or absolute (e.g. 2014-09-18T12:34:56Z). For no expiry, use infinite, indefinite, infinity or never.
wiki.Alumni.NET - Your Location Information Resource
Expiry values may be relative (e.g. 5 months or 2 weeks) or absolute (e.g. 2014-09-18T12:34:56Z). For no expiry, use infinite, indefinite, infinity or never.