Feature summary (what you would like to be able to do and where):
When doing action=query&list=users, add a way to retrieve whether the account is an expired temporary account, similar to the creator_is_expired_temp_account field in action=pagetriagelist.

Use case(s) (list the steps that you performed to discover that problem, and describe the actual underlying problem which you want to solve. Do not describe only a solution):
I am working on a script that identifies users by type, but there is no way exposed by the current API to determine whether an account is a current or expired account other than retrieving the creation time, adding 90 days, comparing it to the current time, and hoping that the math is accurate. Scripts that leave messages for users would also benefit from being able to warn the user that the account they're leaving a message for has been deactivated, the same way it would notify about an account that does not exist.

Benefits (why should this be implemented?):
Any script or external tool that identifies users by type or leaves messages or notices on user talk pages needs to know whether the account is currently expired or not. Having the script do the math based on the registration date is a fragile system that requires extra code overhead and would break if the expiration time is changed or any other changes are made such as allowing renewal or early expiration.