On June 27, 2012, in App Engine release 1.7.0, we announced Alpha support for the PageSpeed service, which is an online service to automatically speed up web pages. While a number of apps enjoy the benefits of PageSpeed, Google has decided to focus its efforts on improving PageSpeed technology through its open-source products.
Accordingly, the PageSpeed service for Google App Engine is deprecated and will be turned off on December 1, 2015. The PageSpeed integration on Google App Engine will continue to function until December 1, 2015, after which date PageSpeed optimizations will no-longer be applied to your app.
No action is required on the part of App Engine users and developers; after the service shutdown on December 1, 2015, apps will continue to operate as before, except without the benefit of the PageSpeed optimizations.
Users who wish to pre-emptively disable PageSpeed can do so following the console instructions.
For more information see the PageSpeed deprecation announcement.