73 can be any value, eval accessed indirectly guarrantees that will be run in global context, in some js engines (that i use that are embeded) the global context cannot be easily determined. If I call this directly I will access local execution context, however I want the js_beautify to be publicly declared.
Eval itself is ok, its useful to have this "last chance" to expose the function if everything else fail :-)

Btw. great library!