The Service Workers builds have been updated as of yesterday, February 22:

Firefox Service Worker Builds

Notable contributions this week were:

• Josh Mathews landed Fetch Event support in Nightly. This is important, of course, because without the Fetch Event you cannot actually intercept any network requests with your Service Worker. | bug 1065216
• Catalin Badea landed more of the Service Worker API in Nightly, including the ability to communicate with the Service Worker using postMessage(). | bug 982726
• Nikhil Marathe landed some more of his spec implementations to handle unloading documents correctly and to treat activations atomically. | bug 1041340 | bug 1130065
• Andrea Marchesini landed fixes for FirefoxOS discovered by the team in Paris. | bug 1133242
• Jose Antonio Olivera Ortega contributed a work-in-progress patch to force Service Worker scripts to update when dom.serviceWorkers.test.enabled is set. | bug 1134329
• I landed my implementation of the Fetch Request and Response clone() methods. | bug 1073231

As always, please let us know if you run into any problems. Thank you for testing!

https://blog.wanderview.com/blog/2015/02/23/that-event-is-so-fetch/