Problem about Ionic platform device class

ionic-v1
1

Ionic platform device class, see from blog http://blog.ionic.io/ionics-first-hack-day/ and http://ionicframework.com/docs/platform-customization/platform-classes.html.

My app will run in Android, so I care these three platform: platform-cordova, platform-webview and platform-android.
I want to known what’s the real difference among these three platform, whether the deployment have difference and how to test them?

2

In the project/www/lib/ionic/ionic.js file, defines var self = ionic.Platform object, then if use cordova+ionic on android 5.1, four platform-xxx classes will added into the document.body:
platform-webview,
platform-cordova,
platform-android,
platform-android5_1
Then one can use these platform classes to override Ionic styling.