Inquiry regarding the internal trigger for FCM push notification registration

[areteruhiro]

Could you please explain the internal logic or the specific trigger that causes the "Allow push notification registration" pop-up to appear (the one that detects GMS Core and adds the app to microG RE, as shown in the attached screenshot)?
​Specifically, I would like to know at what point in the internal process this dialog is prompted to the user.
​Thank you for your time and assistance.

Acknowledgements

• I have checked all open and closed bug reports and this is not a duplicate.

[areteruhiro]

There have been reports that even when a specific app possesses an FCM token, it is sometimes not properly provided to (or detected by) microG. Since I am not deeply familiar with the underlying mechanism myself, I am reaching out to ask for more details on why this might happen.
[FIS][STATE] status=REGISTERED token=eyJhbGciOiJFUzI1NiIsInR5cCI6IkpXVCJ9.eyJhcHBJZCI6IjE6NDU4NjU0OTIyNTphbmRyb2lkOjk1ODFjZjUwNTc3MzdiMzQiLCJleHAiOjE3NzIwMTg1NTMsImZpZCI6ImY4WWllTGp0UzNpQTl6NWxCSHFhZ1UiLCJwcm9qZWN0TnVtYmVyIjo0NTg2NTQ5MjI1fQ.AB2LPV8wRQIhAJiFb0mgK64giuwOD14iTnXUYIchgs7YyOuGR4SK56mHAiAQXQYGtQpRM-4MM8Kn1fn1t6lUcrIdeM22OSTXD98h8w
[ 2026-02-21T08:32:55.508 11166: 9355: 9467 I/LSPosed-Bridge ] [FIS][TOKEN] = eyJhbGciOiJFUzI1NiIsInR5cCI6IkpXVCJ9.eyJhcHBJZCI6IjE6NDU4NjU0OTIyNTphbmRyb2lkOjk1ODFjZjUwNTc3MzdiMzQiLCJleHAiOjE3NzIwMTg1NTMsImZpZCI6ImY4WWllTGp0UzNpQTl6NWxCSHFhZ1UiLCJwcm9qZWN0TnVtYmVyIjo0NTg2NTQ5MjI1fQ.AB2LPV8wRQIhAJiFb0mgK64giuwOD14iTnXUYIchgs7YyOuGR4SK56mHAiAQXQYGtQpRM-4MM8Kn1fn1t6lUcrIdeM22OSTXD98h8w
[ 2026-02-21T08:32:55.516 11166: 9355: 9467 I/LSPosed-Bridge ] ===== fd.t.b() AFTER (FINAL) =====
[ 2026-02-21T08:32:55.516 11166: 9355: 9467 I/LSPosed-Bridge ] key = subtype | value = 4586549225 | type = java.lang.String
[ 2026-02-21T08:32:55.516 11166: 9355: 9467 I/LSPosed-Bridge ] key = sender | value = 4586549225 | type = java.lang.String
[ 2026-02-21T08:32:55.517 11166: 9355: 9467 I/LSPosed-Bridge ] key = app_ver | value = 151220265 | type = java.lang.String
[ 2026-02-21T08:32:55.517 11166: 9355: 9467 I/LSPosed-Bridge ] key = osv | value = 30 | type = java.lang.String
[ 2026-02-21T08:32:55.517 11166: 9355: 9467 I/LSPosed-Bridge ] key = cliv | value = fcm-24.1.1 | type = java.lang.String
[ 2026-02-21T08:32:55.517 11166: 9355: 9467 I/LSPosed-Bridge ] key = gmsv | value = 255034000 | type = java.lang.String
[ 2026-02-21T08:32:55.518 11166: 9355: 9467 I/LSPosed-Bridge ] key = appid | value = f8YieLjtS3iA9z5lBHqagU | type = java.lang.String
[ 2026-02-21T08:32:55.518 11166: 9355: 9467 I/LSPosed-Bridge ] key = scope | value = * | type = java.lang.String
[ 2026-02-21T08:32:55.518 11166: 9355: 9467 I/LSPosed-Bridge ] key = Goog-Firebase-Installations-Auth | value = eyJhbGciOiJFUzI1NiIsInR5cCI6IkpXVCJ9.eyJhcHBJZCI6IjE6NDU4NjU0OTIyNTphbmRyb2lkOjk1ODFjZjUwNTc3MzdiMzQiLCJleHAiOjE3NzIwMTg1NTMsImZpZCI6ImY4WWllTGp0UzNpQTl6NWxCSHFhZ1UiLCJwcm9qZWN0TnVtYmVyIjo0NTg2NTQ5MjI1fQ.AB2LPV8wRQIhAJiFb0mgK64giuwOD14iTnXUYIchgs7YyOuGR4SK56mHAiAQXQYGtQpRM-4MM8Kn1fn1t6lUcrIdeM22OSTXD98h8w | type = java.lang.String
[ 2026-02-21T08:32:55.518 11166: 9355: 9467 I/LSPosed-Bridge ] key = gmp_app_id | value = 1:4586549225:android:9581cf5057737b34 | type = java.lang.String
[ 2026-02-21T08:32:55.518 11166: 9355: 9467 I/LSPosed-Bridge ] key = firebase-app-name-hash | value = R1dAH9Ui7M-ynoznwBdw01tLxhI | type = java.lang.String
[ 2026-02-21T08:32:55.518 11166: 9355: 9467 I/LSPosed-Bridge ] key = app_ver_name | value = 15.12.2 | type = java.lang.String
[ 2026-02-21T08:32:55.519 11166: 9355: 9467 I/LSPosed-Bridge ] ===== END =====
[ 2026-02-21T08:32:55.614 11166: 9355: 9448 I/LSPosed-Bridge ] [FIS][STATE] status=REGISTERED token=eyJhbGciOiJFUzI1NiIsInR5cCI6IkpXVCJ9.eyJhcHBJZCI6IjE6NDU4NjU0OTIyNTphbmRyb2lkOjk1ODFjZjUwNTc3MzdiMzQiLCJleHAiOjE3NzIwMTg1NTMsImZpZCI6ImY4WWllTGp0UzNpQTl6NWxCSHFhZ1UiLCJwcm9qZWN0TnVtYmVyIjo0NTg2NTQ5MjI1fQ.AB2LPV8wRQIhAJiFb0mgK64giuwOD14iTnXUYIchgs7YyOuGR4SK56mHAiAQXQYGtQpRM-4MM8Kn1fn1t6lUcrIdeM22OSTXD98h8w
[ 2026-02-21T08:32:55.618 11166: 9355: 9456 I/LSPosed-Bridge ] [FIS][TOKEN] = eyJhbGciOiJFUzI1NiIsInR5cCI6IkpXVCJ9.eyJhcHBJZCI6IjE6NDU4NjU0OTIyNTphbmRyb2lkOjk1ODFjZjUwNTc3MzdiMzQiLCJleHAiOjE3NzIwMTg1NTMsImZpZCI6ImY4WWllTGp0UzNpQTl6NWxCSHFhZ1UiLCJwcm9qZWN0TnVtYmVyIjo0NTg2NTQ5MjI1fQ.AB2LPV8wRQIhAJiFb0mgK64giuwOD14iTnXUYIchgs7YyOuGR4SK56mHAiAQXQYGtQpRM-4MM8Kn1fn1t6lUcrIdeM22OSTXD98h8w
[ 2026-02-21T08:32:55.709 11166: 9355: 9355 I/LSPosed-Bridge ``