Additional ecma files

I just generated ecmascript files for level1 and 
noticed the following files:

    alltests.js
    mozsafe.js
    readonly.js

What are these files used for?  Curt, can you 
provide a simple overview of how we should 
run the ecmascript harness -- any additional 
code (possibly DOMTestCase.js), and how it 
all fits together?

Thanks,

Mary