Add description for the "Time to wait before releasing an expired item" option

While the Number of completed items to keep in the database option is self-explanatory and all other options on the admin/config/system/advancedqueue page have nice descriptions, the only option remains ambiguous to me is Time to wait before releasing an expired item option.

What is expired item in the context of advanced queue anyway? The ones that failed to process or ones which are waiting for being processed legitimately really long times? I am not sure how the whole process works, but keep wondering if, let's say, annually renewed licenses (billing cycles) get into the advanced queue? And if yes, then we should keep this option to Never for that kind of queue items with really long periods, or we can safely set this to 1 hour, 1 day, 1 week, etc?

Would be really nice to have some kind of description for that option anyway.

Thanks for consideration!