We're going to deploy breaking changes to docs.rs on September 30th: read the blog post to learn what's changing and how to keep your crate documented.
Very interesting! Do you then recommend using this docker (I imagine with some special containment flags) to build untrusted code?
Well, whether you want to use that image or not for sandboxing depends on how much you trust Docker itself. Personally I think it provides a good level of isolation if configured correctly (for example with network access disabled and no write access to persistent data), but I would still execute the builds on a VM with no access to sensitive stuff.