Function: Handles _deprecated_function() errors.

Function: Handles _deprecated_argument() errors.

Function: Sends Cross-Origin Resource Sharing headers with API requests.

Function: Registers a new field on an existing WordPress object type.

Function: Registers rewrite rules for the REST API.

Function: Adds REST rewrite rules.

Function: Registers the default REST API filters.

Function: Registers default REST API routes.

Function: Loads the REST API.

Function: Retrieves the URL prefix for any API resource.