I am trying to set up FCM notifications in my Chrome MV3 extension without having a page open all the time for an FCM service worker, following this guide: https://blog.plasmo.com/p/firebase-cloud-messaging-chrome-extension

It uses the chrome.gcm api. GCM has been deprecated, however the chrome.gcm api is still functional - will this always be the case? According to this forum (https://groups.google.com/a/chromium.org/g/chromium-extensions/c/V6cZ5ORplBY) it seems that chrome.gcm will be deprecated, but also says that it is OK to continue using chrome.gcm.onMessage.

If someone could provide some more concrete details it would be much appreciated.