Hi… Generally, you would access that one through a Docker-specific CLI utility, using a token.
For point-and-click browsing, instead, the dashboard (fly.io/apps/<app-name>/registry) will display a (typically) useful subset without any real effort needed.
There are some tips and caveats in this thread from two months ago:
https://community.fly.io/t/should-every-app-have-entries-in-the-registry/26237
Hope this helps!