JWS 3.1.0 Tomcat 8 includes different JSP compiler version than Open Source Tomcat 8.0.36

Issue

• JWS 3.1.0 Tomcat 8 includes different Java Servlet Pages (JSP) compiler version than Open Source Tomcat 8.0.36.
• Why JWS 3.1.0 Tomcat 8 includes lower/different version of ecj jar?
• JWS 3.1.0 claims to be based on Tomcat 8.0.36 but why ecj jar version is different than one available in community Tomcat 8.0.36?
• Why JWS 3.1.0 includes ecj-4.4.2-eap6.jar version but Tomcat 8.0.36 includes ecj-4.5.jar version ?