Source Stamp Information

I was reading through the Play App Signing documentation and could see that the Bundletool injects a source stamp into the generated Apks. I wanted to understand how this source stamp is used by Google for Verification of apps. Is there also a use case where the apps verify that the playstore they are working with is google?

When I try to verify the apk signature using apksigner I can see that the output is no source stamp signature injected. Is this expected behaviour?[Adding output of apksigner v33]

```
Signer #1 certificate DN: CN=ss, OU=ss, O=ss, L=ss, ST=ss, C=ss
Signer #1 certificate SHA-256 digest: 9376d837c0d3a84bb3b6f91238a672a53d1c31a1ca490df536a2f44ef55e8489
Signer #1 certificate SHA-1 digest: 3b0da8acde9b977c511c0748fac49af96f5abca4
Signer #1 certificate MD5 digest: 8972eb195b283d1bbd799cef7b88eacf
WARNING: META-INF/androidx.appcompat_appcompat.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.arch.core_core-runtime.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.asynclayoutinflater_asynclayoutinflater.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.coordinatorlayout_coordinatorlayout.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.core_core.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.cursoradapter_cursoradapter.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.customview_customview.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.documentfile_documentfile.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.drawerlayout_drawerlayout.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.fragment_fragment.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.interpolator_interpolator.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.legacy_legacy-support-core-ui.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.legacy_legacy-support-core-utils.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.lifecycle_lifecycle-livedata-core.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.lifecycle_lifecycle-livedata.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.lifecycle_lifecycle-runtime.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.lifecycle_lifecycle-viewmodel.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.loader_loader.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.localbroadcastmanager_localbroadcastmanager.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.print_print.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.slidingpanelayout_slidingpanelayout.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.swiperefreshlayout_swiperefreshlayout.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.vectordrawable_vectordrawable-animated.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.vectordrawable_vectordrawable.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: META-INF/androidx.viewpager_viewpager.version not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.
WARNING: No SourceStamp signature
```

WARNING: No SourceStamp signature -> Source Stamp signature not present.