我已经创建了一个新的Flutter项目，minSdkVersion在app/build.gradle文件中的外观如下：

defaultConfig {
    // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
    applicationId "com.example.projectname"
    minSdkVersion flutter.minSdkVersion
    targetSdkVersion flutter.targetSdkVersion
    versionCode flutterVersionCode.toInteger()
    versionName flutterVersionName
}

flutter.minSdkVersion的值设置在哪里？
请注意，以前的配置值如下所示：

defaultConfig {
    // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
    applicationId "com.example.projectname"
    minSdkVersion 19 //*** This is the part that needs to be changed, previously was 16
    targetSdkVersion 28
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}

另外，这是android/local.properties文件的内容：

sdk.dir=/Users/usernaem/Library/Android/sdk
flutter.sdk=/Users/username/flutter
flutter.buildMode=release
flutter.versionName=1.0.0
flutter.versionCode=1

正如您所看到的，flutter.minSdkVersion的值没有在那里设置，但是可以成功地编译和构建项目。
变量flutter.minSdkVersion和flutter.targetSdkVersion在哪里初始化？
P.S.相关问题：https://github.com/flutter/flutter/issues/95533