'zlib' nodejs core module browserify-ied with --standalone zlib. Should support all module systems (commonjs, AMD & window.zlib) - check browserify docs.
From node2web collection, should/will be exposed as 'zlib' to bower for browser usage.
browserify version: '3.46.1', build date 'Wed Oct 08 2014 17:38:46 GMT+0300 (EEST)'