What is the difference between:

1. RestTemplate created with new:

var t = new RestTemplate();

2. RestTemplate created with the auto-configured RestTemplateBuilder

@Autowired
RestTemplateBuilder builder;

...
public void xyz() {
  var t = builder.build();
}

3. RestTemplate created from a new RestTemplateBuilder:

var t = new RestTemplateBuilder().build();

According to
Spring Documentation:

Spring Boot does not provide any single auto-configured RestTemplate bean. It does, however, auto-configure a RestTemplateBuilder, which can be used to create RestTemplate instances when needed. The auto-configured RestTemplateBuilder ensures that sensible HttpMessageConverters and an appropriate ClientHttpRequestFactory are applied to RestTemplate instances.

But what are the additional HttpMessageConverters added?
And should #1 and #2 return RestTemplate with the exact same configuration?