During an org to org deployment, what is replaced with the destination environment?

In the context of an org to org deployment, environment variables are specifically designed to store values that can change between environments. When deploying from one organization to another, all environment variables in the source org are replaced with their corresponding values in the destination environment. This ensures that the deployment is tailored to function correctly in the new context, taking into account any unique settings or configurations needed for the destination.

Metadata records, while essential in deployments, refer to the various components of Salesforce such as custom objects, fields, and apex classes, which are transferred without being replaced by environment-specific settings. Mapping files generally serve to establish relationships and references between different components but do not change during deployment. Similarly, "All Maps" is too broad a term and may refer to various configurations or settings that are not specifically tied to environment variable changes during the deployment process. Thus, environment variables are the key elements that are specifically intended for alteration to align the deployment with the destination environment's configurations and settings.