How to find declaration of "flutter dot" constants contained in build.gradle?

Question

When creating a new flutter project (these days, 2023), it uses external constants for the min, target, and compile SDKs like this:

defaultConfig {
        applicationId "com.example.blah"
        minSdkVersion flutter.minSdkVersion
        targetSdkVersion flutter.targetSdkVersion
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
    }

Where can I find where these "flutter." constants are stored/declared? I tried right click, "go to declaration" but it doesn't work. The IDE (Android Studio) is treating it as if it were just plain text.