Page Speed for Chrome
To enable the developers to port to Chrome, they have created a C++ SDK for Page Speed. The Firefox extension will be migrated to use the Page Speed SDK in a future version, allowing Google to keep both editions feature equivelant. Currently the new Chrome extension has an advantage as it has improved scoring and suggestion ordering which allows developers to see optimisations with higher potential first. The Chrome extension is also capable of displaying the recommendations in forty languages.
Page Speed, the extension and the SDK, are available under the Apache 2.0 licence. Instructions for installing Page Speed for Chrome are also available which show how to enable the experimental extensions API in Chrome which Page Speed uses.