Spring Boot 1.5.3.RELEASE had several classes in org.springframework.boot.context.embed and also the subpackages jetty, tomcat, and undertow. However, https://github.com/spring-projects/spring-boot/tree/v2.0.0.M1/spring-boot/src/main/java/org/springframework/boot/context doesn't contain the subdirectory embed anymore.
Where are classes like TomcatEmbeddedServletContainerFactory gone?