How long does media URL's stay active after their parent object have been removed?

When saving media to an object (a photo for example), the actual media file is saved somewhere else on AWS and the URL to that media file gets stored on the backend database. I have noticed that when this object containing the media is removed, the URL to the media file is still active, i.e. navigating to the URL will display the photo in the browser. How long will this URL remain active?

Briefly, an attachment is deleted from AWS 30 days after all objects in the DB that link to the attachment have been deleted, but if you "re-link" the attachments within in those 30 days then they will not be removed.

I.e. if you delete objects from App A, and create new objects in App B that link to the attachments in App A, then the attachments won't be deleted (if that happens within 30 days).