Is it possible to cast a Chrome browser tab from desktop to an Android (OS 8.1) device? My goal is to mirror the content from that Chrome desktop tab on my Android device.
You can install WebRTC Desktop Sharing extension on your Chrome browser for Desktop. Click on its icon → Chrome tab + Speakers → choose your tab to share → wait for the extension to give you a URL.
Use that URL into your Android device's browser. It will take few seconds to initialize everything and then you can have a real-time Chrome tab sharing from Desktop to anywhere.
Alternatively, if you are using Windows, enable Remote Desktop Sharing in it, setup a Remote Desktop connection and use Chrome Remote Desktop app to share the whole screen with Android. I haven't tested this one though.