[Android Software Development] ipdev:
Bit OT for this thread but...

For a Flashable installer ZIP file..

META-INF/com/google/android/update-binary
META-INF/com/google/android/updater-script

are required.

Years ago..

Chainfire figured out how to use a script file for installation instead of building an install binary file.

For more information using a script file instead of a binary.

xdaThread - [DEV][TEMPLATE] Complete Shell Script Flashable Zip Replacement + Signing [SCRIPT] - Link

Example of flashable zip file.

MindTheGapps-12.1.0-arm64-20220528_014753.zip

[ip@lost out]$ unzip -l MindTheGapps-12.1.0-arm64-20220528_014753.zip
Archive: MindTheGapps-12.1.0-arm64-20220528_014753.zip
signed by SignApk
Length Date Time Name
--------- ---------- ----- ----
8896 02-28-2008 20:33 META-INF/com/google/android/update-binary
79 02-28-2008 20:33 META-INF/com/google/android/updater-script
44 02-28-2008 20:33 build.prop
120 02-28-2008 20:33 system/addon.d/addond_head
572 02-28-2008 20:33 system/addon.d/addond_tail
2484539 02-28-2008 20:33 system/product/app/GoogleCalendarSyncAdapter/GoogleCalendarSyncAdapter.apk
1505961 02-28-2008 20:33 system/product/app/GoogleContactsSyncAdapter/GoogleContactsSyncAdapter.apk
1707872 02-28-2008 20:33 system/product/app/MarkupGoogle/MarkupGoogle.apk
2019184 02-28-2008 20:33 system/product/app/MarkupGoogle/lib/arm64/libsketchology_native.so
491242 02-28-2008 20:33 system/product/app/PrebuiltExchange3Google/PrebuiltExchange3Google.apk
63306025 02-28-2008 20:33 system/product/app/SpeechServicesByGoogle/SpeechServicesByGoogle.apk
29225581 02-28-2008 20:33 system/product/app/talkback/talkback.apk
1488 02-28-2008 20:33 system/product/etc/default-permissions/default-permissions-google.xml
610 02-28-2008 20:33 system/product/etc/permissions/com.google.android.dialer.support.xml
20560 02-28-2008 20:33 system/product/etc/permissions/privapp-permissions-google-product.xml
1484 02-28-2008 20:33 system/product/etc/security/fsverity/gms_fsverity_cert.der
136 02-28-2008 20:33 system/product/etc/sysconfig/d2d_cable_migration_feature.xml
4259 02-28-2008 20:33 system/product/etc/sysconfig/google-hiddenapi-package-allowlist.xml
3960 02-28-2008 20:33 system/product/etc/sysconfig/google.xml
1106 02-28-2008 20:33 system/product/etc/sysconfig/google_build.xml
946 02-28-2008 20:33 system/product/framework/com.google.android.dialer.support.jar
943652 02-28-2008 20:33 system/product/lib/libjni_latinimegoogle.so
1112352 02-28-2008 20:33 system/product/lib64/libjni_latinimegoogle.so
2213270 02-28-2008 20:33 system/product/priv-app/AndroidAutoStub/AndroidAutoStub.apk
110342415 02-28-2008 20:33 system/product/priv-app/GmsCore/GmsCore.apk
722022 02-28-2008 20:33 system/product/priv-app/GooglePartnerSetup/GooglePartnerSetup.apk
9497023 02-28-2008 20:33 system/product/priv-app/GoogleRestore/GoogleRestore.apk
59512415 02-28-2008 20:33 system/product/priv-app/Phonesky/Phonesky.apk
257583310 02-28-2008 20:33 system/product/priv-app/Velvet/Velvet.apk
3975 02-28-2008 20:33 system/system_ext/etc/permissions/privapp-permissions-google-system-ext.xml
691385 02-28-2008 20:33 system/system_ext/priv-app/GoogleFeedback/GoogleFeedback.apk
7394360 02-28-2008 20:33 system/system_ext/priv-app/GoogleServicesFramework/GoogleServicesFramework.apk
8250928 02-28-2008 20:33 system/system_ext/priv-app/SetupWizard/SetupWizard.apk
1579256 02-28-2008 20:33 toybox
1675 02-28-2008 20:33 META-INF/com/android/otacert
3764 02-28-2008 20:33 META-INF/MANIFEST.MF
4132 02-28-2008 20:33 META-INF/CERT.SF
1714 02-28-2008 20:33 META-INF/CERT.RSA
--------- -------
560642312 38 files
[ip@lost out]$

Remove only what you want to modify and then zip the rest back the same as the original zip file.

Cheers all. :cowboy: