how do I track down the cause of this error

Question

* What went wrong:
Execution failed for task ':app:checkDebugAarMetadata'.
> A failure occurred while executing com.android.build.gradle.internal.tasks.CheckAarMetadataWorkAction
   > The minCompileSdk (31) specified in a
     dependency's AAR metadata (META-INF/com/android/build/gradle/aar-metadata.properties)
     is greater than this module's compileSdkVersion (android-30).
     Dependency: androidx.browser:browser:1.4.0.
     AAR metadata file: /Users/markj/.gradle/caches/transforms-3/fedb1dfce730f31190923d6e253eb6c6/transformed/browser-1.4.0/META-INF/com/android/build/gradle/aar-metadata.properties.

I'm using cordova 11.0.0 and cordova android 10.1.2

I've just added admob-plus-cordova as described at https://admob-plus.github.io/docs/cordova/installation

I have only done

cordova plugin add admob-plus-cordova --save --variable APP_ID_ANDROID=ca-app-pub-xxx~xxx --variable APP_ID_IOS=ca-app-pub-xxx~xxx

because the other instructions didn't seem to apply to my situation