Understanding Class Loaders - Apache Tomcat?

Module Development
1
  1. In the following chapter of the :
    Ignition SDK Programmer’s Guide Ignition SDK Programmers Guide Getting Started

docs.inductiveautomation.com:84 … ss+Loaders

the diagram for the Gateway shows dependency on the Apache Tomcat. Why?

  1. Does the Gateway use Apache Tomcat or Jetty framework?
2

It used to use Tomcat, now it uses Jetty.