Auto expire flag

Similar to this request from 3 years ago, I'd like to auto-expire some flags. We add "breaking" and "developing" flags to many stories. These flags make sense when they're added, but after a few hours (definitely after a few days) they can be confusing to readers. I'd like for those flags to disappear after a set amount of time. I can recommend how much time that is, or you can let individual sites set that time. 

I don't want to remove the flag — we're using those flags to track stories. (So we can tell reporters whether breaking news stories perform better than an enterprise story, for example.) But if the flag was not visible to the reader after X hours, then I'd have the best of both worlds.

So this is my official feature request. It would solve the problem outlined above. It would be used daily. It would be used by/available to all of our reporters and editors.