Support for new option to include features into the default bundle.
Since Chrome 41, the version Google uses for indexing, does not support a lot of new functionality. Polyfills will most certainly be loaded. This will reduce Pagespeed.
feature.include
Now you can set the include property of a feature to true. This will make sure the polyfill will be included into the default bundle. It will still not execute if the feature is detected. But only loaded and parsed.