When I built a private repository of Bitbucket I prepared for testing, I can see the build result even by a non login user.
Bitbucket Private repository: https://bitbucket.org/khasegawa_net/circle-ci-test
Build Result: https://circleci.com/bb/khasegawa_net/circle-ci-test
Is this a bug?
You can also download it by entering artifacts / containers / 0
etc in the URL fragment.