Archived projects are only visible in the admin area
GitLab has long had a concept of "archived" projects, which disable writing to the associated repository and was supposed to lower the visibility while still making it available to you.
At some point we removed the visibility entirely, and as far as I can tell now, you can only find an archived project via the administration panel. It's not shown on your Projects dashboard, on the containing Group's list of projects, or even on your personal dashboard.
We need some UX work to make them less visible, but not completely invisible.
Related: https://gitlab.com/gitlab-org/gitlab-ce/issues/30743
Slack discussion: https://gitlab.slack.com/archives/C0GQHHPGW/p1491862490836323
cc @tauriedavis