Anyone facing this problem after targetSdk 31 when using extensions has two options:
Contact the extension developer(s) and ask them to declare this (
android:exported="true"for activities, broadcast receivers) in the Manifest.Build the APK, decompile it, declare it in the Manifest, recompile the APK, convert the APK to AAB and sign it. See also here: New App API Level 31 In Console - #2 by Anke - Discuss - Niotron Community
Example:
Note: Taifun has already fixed it in his today's new extension version (sent to me via PM).