Consider adding something granting access to secrets or credentials in the host credential storage.

I've just opened https://github.com/microsoft/vscode-remote-release/issues/10470, asking for a generic credential helper to be forwarded into VSCode's devcontainer implementation.

This issue is something about looking at it from the other side of that, asking about whether something related to that should be added to the spec. This might be something like a permissions scheme for specific credentials, setting the path of the (default) credential helper, or setting a separate username for a specific host.

I have seen https://github.com/devcontainers/spec/issues/198, but I'm specifically thinking of usage apart from environment variables here. Besides any potential security benefits, it would also work for tools that may not allow configuration via environment variables.