Why does Closure Compiler not rename objects with certain names?

Question

When I test the following code in closure compiler at http://closure-compiler.appspot.com:

// ==ClosureCompiler==
// @output_file_name default.js
// @compilation         


        

Answer 1

Update

As of the 20150315 release of Closure-compiler, the type based optimizations are enabled by default.

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Closure Compiler will not rename properties that have the same name as any property defined on an object in the externs unless the --use_types_for_optimization flag is enabled. See the project FAQ for more details.