Publish apksigner output & remove not needed files in META-INF

[emanuelb]

In order to verify direct APK download from github/google-play/(mirror/download)-websites the output from apksigner is needed.
see for example the verification section in aegis app:
https://github.com/beemdevelopment/Aegis#verification

Running apksigner (Command: apksigner verify --print-certs --verbose latest.apk) on apk downloaded from website:
https://exchangily.com/download/latest.apk
sha256sum: 15b1cd5217c828e36888ca35febb7f32a872f9e9b4e101c8ede827fa0ba5d540

Result:

Verifies
Verified using v1 scheme (JAR signing): true
Verified using v2 scheme (APK Signature Scheme v2): true
Verified using v3 scheme (APK Signature Scheme v3): false
Number of signers: 1
Signer #1 certificate DN: CN=Paul Liu, OU=7300 Warden Ave, O=Exchangily, L=Markham, ST=ON, C=CA
Signer #1 certificate SHA-256 digest: 86f1008519cbd4f77c68401d1ecaa8d157310bc0d3d6bef870c6c9f66a8734f9
Signer #1 certificate SHA-1 digest: 17a2f11ab724b9d79b5bb7879e80d4e3251d785c
Signer #1 certificate MD5 digest: 12d460839f9af728e0b7d6d1b9ad22a6
Signer #1 key algorithm: RSA
Signer #1 key size (bits): 2048
Signer #1 public key SHA-256 digest: e1791b1af4ef7c7ed4af065a7633e759b74b3028ccabd69252e59331e365a752
Signer #1 public key SHA-1 digest: 5fa395d8568037fee3bff6e1b0aa2e57a2731395
Signer #1 public key MD5 digest: c006afb65b7bdef04bbbbc1c337468ba
WARNING: META-INF/androidx.activity_activity.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.annotation_annotation-experimental.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.appcompat_appcompat-resources.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.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.biometric_biometric.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.browser_browser.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.cardview_cardview.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.legacy_legacy-support-v4.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-savedstate.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.media_media.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.recyclerview_recyclerview.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.savedstate_savedstate.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.tracing_tracing.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.transition_transition.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.versionedparcelable_versionedparcelable.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.viewpager2_viewpager2.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: META-INF/androidx.webkit_webkit.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/annotation-experimental_release.kotlin_module 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/app_release.kotlin_module 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/barcode_scan_release.kotlin_module 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/com.google.android.material_material.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/kotlin-stdlib-common-coroutines.kotlin_module 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/kotlin-stdlib-common.kotlin_module 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/kotlin-stdlib-coroutines.kotlin_module 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/kotlin-stdlib-jdk7.kotlin_module 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/kotlin-stdlib.kotlin_module 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/wakelock_release.kotlin_module not protected by signature. Unauthorized modifications to this JAR entry will not be detected. Delete or move the entry outside of META-INF/.

All the files in WARNING should be removed or moved to other directory, it's not much problematic because apk also signed with v2, when v1 verification is used (which is deprecated from 2016) the files in WARNING are not authenticated ("Unauthorized modifications to this JAR entry will not be detected.")

They probably should be removed, which can be done for example by adding exclude lines to packagingOptions in build.gradle file.

see related question on stackoverflow for info on removing such files:
https://stackoverflow.com/questions/66897483/how-can-i-exclude-all-files-in-meta-inf-except-for-the-three-signature-files

This also create non reproducibility issues in files inside META-INF directroy, see issue: #4 (comment)