Archived Courses are “courses that ran their course” on Kadenze. You won’t be able to make any changes to an Archived course, or submit coursework, but you can always access it to see your grade, the forums, session videos etc.
Any course that you were enrolled in at the time of its completion* will be permanently available to you on Kadenze, in the Archived tab of My Courses.
*This includes courses which ended and restarted. The two versions are technically different, so if you were enrolled in the old one, you’ll still see it in your Archived courses.