FYI. Please also see: -
http://stackoverflow.com/questions/36764108/changing-firefox-push-message-provider
https://github.com/w3c/push-api/issues/189

Both Chrome and Mozilla are prioritizing producing interoperable implementations of the parts of the API that are exposed to developers (Push API on the client side, and Web Push on the server side).

Currently different browsers communicate with their corresponding push services in different ways, so there is no such URL that can be swapped in to switch the push service used by the browser.

Can you please explain why this is "wontfix"?

Given that some European Court with sooner rather than later decree that it is an abuse of market position for a browser manufacturer to mandate the use of it's proprietary Push Notification Service, just as it would be for Google to mandate your search engine for Chrome or Bing for Edge, why the recalcitrance?

Push Services who don't have the luxury of also manufacturing a browser must be able to compete with you or Mozilla or Microsoft! Maybe they're faster, Cheaper, more secure, local, who knows?

I wouldn't have thought that Google Goose-Stepping over start-up Push Notification Services was an image you'd wish to portray to the anti-competitive-practices authorities? 

http://ec.europa.eu/competition/elojade/isef/case_details.cfm?proc_code=1_40099 

Do I really have to spend my week-end writing to the European Commissioner in order to bolster their case against your abuse or Android Market Dominance, or are you going to see sense?

You have to use our flavour of Android! 
You have to use Chrome! 
You have to install Google Play!
Google Search must be the default search engine!
GCM (sorry FCM) must be your Push Notification Service!

Oh, and "Don't be evil". Really?

There's a w/e I won't get back. Seeing as how you insist: -

From: Richard's Hotmail 
Sent: Monday, July 18, 2016 7:54 PM
To: 'comp-greffe-antitrust@ec.europa.eu'
Subject: Re: Competition Case - 40099 Google Android

Further to the above case currently before the European Commission ( http://ec.europa.eu/competition/elojade/isef/case_details.cfm?proc_code=1_40099 ), I wish to bring to your attention to what, in my view, is potentially a far more egregious example of Google's abuse of market dominance in the Android market place.

Unlike the "search service" referenced in the original case before the Commission, my complaint deals with the deployment of Google's "push notification service" Google-Cloud-Messaging (GCM), or as it has recently been rebadged, Firebase-Cloud-Messaging (FCM).

Whereas a Search Service can be easily changed via a user-selectable browser Option, the choice of Push Service for all Android Chrome, Opera, and Samsung/Android browser users is mandated to be Google's GCM Push Service. This bundling of services is hidden from the users' view and incapable of modification on the 3 browsers mentioned. (For an example of a browser that does facilitate a choice of Push Service, please see Mozilla's Firefox. The Firefox Configuration Editor (about:config page) currently permits the user to select a different push service via the services.push.serverURL parameter)

With GCM's monopoly of exclusive deployment to the 3 most popular Android Web Browsers, access to the Push Service market is hindered for all other Push Service providers, especially if they do not also happen to be browser manufacturers. Thus they are excluded by Google from the opportunity of competing on price, service, or features.

Additional points of relevance: -
[1] The specifications dealing with plug-and-play standards for browsers and Push Notification Services are:
-- Client https://www.w3.org/TR/push-api/ 
-- Server https://tools.ietf.org/html/draft-ietf-webpush-protocol-07  
[2] Any interim opinion or decision from the Commission would be quite timely as Microsoft is currently implementing the Push API for its own Edge browser. As with Google's GCM on Android, Microsoft's Azure Notification Hubs should not be permitted to monopolize the Push Service market on Windows/Edge.
[3] I have no knowledge of any business relationships that Opera and/or Samsung have with Google regarding their deployment of GCM clients, or why Samsung have self-limited their Push Service target-market to "only for Samsung services (Samsung Apps, Samsung Link, Samsung Wallet, Samsung Pay, etc.)"
[4] Push Notification functionality, in its current form, is very new to the browser world but destined for ubiquitous HTML5 Web App deployment. We must ensure that competition can thrive.
[5] I do not envisage that Google wrote specific or individual GCM APIs for Samsung and Opera. Therefore I see no reason why this GCM API cannot be made available to Firefox users as well. As much as one Chrome user may choose to use Mozilla's Autopush Notification Service, another browser user may wish to use GCM for their Firefox notifications.

Please don't hesitate to contact me if should you require clarification of additional information.

Please also note that the above is purely my personal opinion. I trust you'll agree that it merits further investigation.

Regards,
Richard Maher

™ All trademarks are the property of their respective owners.

God bless Firecast and Chrome people with vision that don't frequent Monorail: -
https://firebase.google.com/docs/cloud-messaging/js/client