How can Google detect a request is from a WebView?

Question

Google announced that they \"will no longer allow OAuth requests to Google in embedded browsers known as \'web-views\'\".

In Android, requests from WebViews get

Answer 1

All http requests sent through a webview have X-Requested-With header present which can be used to detect that the request is from webview.

X-Requested-With: the.app.packageName