Can I archive projects?

Yes, you can archive projects. This is useful if a project has been completed or is no longer being worked on, and you prefer to keep it around instead of deleting it. Archived projects are not shown in the Overview page and various other places, so archiving projects helps to avoid clutter. Archived projects are still available, and you can still select them and make changes to them. And you can unarchive an archived project anytime you want.

To archive a project, open its popup dialog and click "Archive" in the bottom of the dialog:

You can also select one or more projects and use the right-click menu to archive them.