Thanks.  SMC projects are private by default, but it does let users easily selectively publish any file or directory tree publicly.   For example: <a href="https:&#x2F;&#x2F;cloud.sagemath.com&#x2F;projects&#x2F;4a5f0542-5873-4eed-a85c-a18c706e8bcd&#x2F;files&#x2F;support&#x2F;" rel="nofollow">https:&#x2F;&#x2F;cloud.sagemath.com&#x2F;projects&#x2F;4a5f0542-5873-4eed-a85c-...</a>