What is the use of gwt-api-checker.jar in GWT 2.0.3

[Charan kumar sarvepalli]

Hi,

I was developing a GWT app in 2.0.3 version.
I have seen two files newly added gwt-api-checker.jar and gwt-soyc-vis.jar
i never used any of these jars files in my app development.
Anyone can tell me what is purpose of these jars files.