Which of the following is NOT a deployment method for custom settings?

The option representing a .gitignore file is not a deployment method for custom settings. A .gitignore file is utilized in version control systems, like Git, to specify files or directories that should not be tracked by the system. Its primary function is to help manage which files are included in the versioning of a project, especially for files that are generated or contain sensitive information that should not be shared.

In contrast, deployment scripts, change sets, and environment variables are all relevant methods for deploying custom settings. Deployment scripts are valuable in automating the process of moving configurations and data between different environments. Change sets provide a user-friendly way to select and deploy metadata and custom settings between Salesforce environments. Environment variables can also be utilized to manage configuration settings across different environments, offering a way to modify behaviors without changing the code.

Thus, the option regarding the .gitignore file distinctly stands apart from these deployment techniques, as it does not directly facilitate the deployment of custom settings.