Hi @Anonymous,
Welcome to the Fusion 360 Community!
I saw your other post as well, but let's just post in this one for the thread's sake.
I'm assuming you are referring to when you right-click a project and select "Archive"? What this does is just makes it so project members can no longer access the project, existing content in the project will no longer be accessible to project members, no new content/activity can be added, and the project will no longer appear in the projects list.
You can reactivate the archived project by visiting your A360 hub here. This website is essentially your data panel. It is is where all of your files is stored on line and can be manually accessed through the web browser (and viewed!)
To reactivate the project, as soon as you visit A360 (the link above), you will see 4 options along the top (All, Owned by me, Shared by me, Archived). If you select Archived you can see your archived projects and then restore them (or fully delete them).

Hope this helps! Let me know if you have any other questions.
Thanks,
James Youmatz
Product Insights Specialist for Fusion 360, Simulation, Generative Design