What causes this call to Firebase server?

An Android app does not use Firebase. I have done a global search to ensure nothing has the word "firebase". However, I see the following logcat entry:

> TRuntime.C...ortBackend com.mydomain.myapp I Making request to: https://firebaselogging.googleapis.com/v0cc/log/batch?format=json_proto3

Could anyone offer a tip to help figure out what triggers this?

The app does not use any third-party analytics or advertising packages.

Update [2023-05-25]

Here are the dependencies of the app:

   implementation "androidx.activity:activity:1.7.1"
    implementation 'androidx.fragment:fragment:1.5.7'
    implementation "androidx.navigation:navigation-fragment:2.5.3"
    implementation "androidx.navigation:navigation-ui:2.5.3"
    implementation "androidx.preference:preference:1.2.0"
    implementation "androidx.datastore:datastore:1.0.0"
    implementation 'androidx.gridlayout:gridlayout:1.0.0'

    implementation 'androidx.work:work-runtime:2.8.1'

    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
    implementation 'androidx.recyclerview:recyclerview:1.3.0'
    implementation 'androidx.browser:browser:1.5.0'

    implementation 'com.google.android.gms:play-services-plus:17.0.0'
    implementation 'com.google.android.gms:play-services-auth:20.5.0'
    implementation 'com.google.android.gms:play-services-location:21.0.1'
    implementation('com.google.guava:guava:30.1.1-android') {
        exclude group: "com.google.guava"
    }

    implementation 'com.google.android.gms:play-services-oss-licenses:17.0.1'

    implementation 'androidx.multidex:multidex:2.0.1'

    implementation 'joda-time:joda-time:2.10.10'

    implementation 'com.github.angads25:filepicker:1.1.1'

    implementation 'commons-io:commons-io:2.5'

    implementation 'com.google.android.flexbox:flexbox:3.0.0'
    implementation 'com.google.android.ads.consent:consent-library:1.0.8'

    implementation 'com.github.hedzr:android-file-chooser:d7b831bf0a'


    implementation('com.google.http-client:google-http-client-gson:1.26.0') {
        exclude group: 'org.apache.httpcomponents'
    }
    implementation('com.google.api-client:google-api-client-android:1.26.0') {
        exclude group: 'org.apache.httpcomponents'
    }
    implementation('com.google.apis:google-api-services-drive:v3-rev136-1.25.0') {
        exclude group: 'org.apache.httpcomponents'
    }

    implementation 'com.android.billingclient:billing:6.0.0'

    implementation 'androidx.appcompat:appcompat:1.6.1'
    implementation 'com.google.android.material:material:1.9.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.1.4'
    implementation 'org.apache.commons:commons-lang3:3.11'

Update [2023-05-25]

I started to look into this after I observed the app crashes consistently following:

> Making request to:
> https://firebaselogging.googleapis.com/v0cc/log/batch?format=json_proto3

As far as I know, this started to happen only recently after I updated some dependencies.
Here is the crash:

StrictMode policy violation: android.os.strictmode.UntaggedSocketViolation: Untagged socket detected; use TrafficStats.setThreadSocketTag() to track all network usage
    at android.os.StrictMode.onUntaggedSocket(StrictMode.java:2023)
    at com.android.server.NetworkManagementSocketTagger.tag(NetworkManagementSocketTagger.java:82)
    at libcore.io.BlockGuardOs.tagSocket(BlockGuardOs.java:50)
    at libcore.io.BlockGuardOs.socket(BlockGuardOs.java:313)
    at libcore.io.IoBridge.socket(IoBridge.java:640)
    at java.net.PlainSocketImpl.socketCreate(PlainSocketImpl.java:124)
    at java.net.AbstractPlainSocketImpl.create(AbstractPlainSocketImpl.java:128)
    at java.net.Socket.createImpl(Socket.java:489)
    at java.net.Socket.getImpl(Socket.java:552)
    at java.net.Socket.setSoTimeout(Socket.java:1180)
    at com.android.okhttp.internal.io.RealConnection.connectSocket(RealConnection.java:139)
    at com.android.okhttp.internal.io.RealConnection.connect(RealConnection.java:112)
    at com.android.okhttp.internal.http.StreamAllocation.findConnection(StreamAllocation.java:184)
    at com.android.okhttp.internal.http.StreamAllocation.findHealthyConnection(StreamAllocation.java:126)
    at com.android.okhttp.internal.http.StreamAllocation.newStream(StreamAllocation.java:95)
    at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:281)
    at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:224)
    at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:461)
    at com.android.okhttp.internal.huc.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:127)
    at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getOutputStream(HttpURLConnectionImpl.java:258)
    at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getOutputStream(DelegatingHttpsURLConnection.java:218)
    at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getOutputStream(HttpsURLConnectionImpl.java:26)
    at com.google.android.datatransport.cct.CctTransportBackend.doSend(CctTransportBackend.java:303)
    at com.google.android.datatransport.cct.CctTransportBackend.$r8$lambda$bLAzIpNF4NtapXlUpPVGhzxyNT8(Unknown Source:0)
    at com.google.android.datatransport.cct.CctTransportBackend$$ExternalSyntheticLambda0.apply(Unknown Source:4)
    at com.google.android.datatransport.runtime.retries.Retries.retry(Retries.java:54)
    at com.google.android.datatransport.cct.CctTransportBackend.send(CctTransportBackend.java:372)
    at com.google.android.datatransport.runtime.scheduling.jobscheduling.Uploader.logAndUpdateState(Uploader.java:146)
    at com.google.android.datatransport.runtime.scheduling.jobscheduling.Uploader.lambda$upload$1$com-google-android-datatransport-runtime-scheduling-jobscheduling-Uploader(Uploader.java:105)
    at com.google.android.datatransport.runtime.scheduling.jobscheduling.Uploader$$ExternalSyntheticLambda2.run(Unknown Source:8)
    at com.google.android.datatransport.runtime.SafeLoggingExecutor$SafeLoggingRunnable.run(SafeLoggingExecutor.java:47)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
    at java.lang.Thread.run(Thread.java:764)

Update [2023-07-21]

The complete logcat entry of the Firebase call that causes the crash:

> I/TRuntime.CctTransportBackend: Making request to:
> https://firebaselogging.googleapis.com/v0cc/log/batch?format=json_proto3

firebaser here

tl;dr: many non-Firebase Google use the https://firebaselogging.googleapis.com/ endpoint to log data to Google's servers, so calls to that endpoint do not have to originate from Firebase SDKs.

Most Google developer products that come with an SDK use a common infrastructure for logging application specific data from within the app back to Google. They use common endpoints for sending this logging, so that they can combine API calls from multiple SDKs into a single call to the logging backend - reducing/amortize the overhead of the logging.

At some point many of the SDKs for Google developer products switched over from a Google-branded endpoint to using a Firebase-branded endpoint. But the data flows is the same either way, and calls to the https://firebaselogging.googleapis.com/ does not necessarily mean that the product uses a Firebase SDK.

This is indeed confusing though, so I raised an issue internally to consider changing to a single Google-branded endpoint again, or to use a per-product endpoint (which would lose some of the amortization benefits mentioned earlier.