Ask HN: How do you handle certificate and password dependencies in your code?

In order to build or deploy a project, often certificates or passwords are required.

Obviously those dependencies should not be explicitly in the project's source code.

But I believe its still good practice to have them versioned with redundancy from corruption or loss.

How do you handle securing those dependencies? And then referencing them in your projects?

Often I see developers make them part of the environment, but that implies that it is versioned somewhere (provided your environment is deployable).

Or rely on syncing with certificate services (like Apple Developer/Xcode), but that isn't always available or not easily accessible.