Google WebView App is out of Beta and is now available for the devices running ANdroid 5.0+. It i snow a system app and can receive system updates regularly directly via Play Store.
WebView is the system component developers use to render webpages inside apps as opposed to sending the user to a separate browser. This allows manufacturers to push out feature and security updates as needed rather than have to perform a complete operating system update just to get these sorts of system apps to their latest versions.
It is now available to all the devices running the Android 5.0 Lollipop. Google decoupled it from the system few weeks ago and was present on Play Store as beta version. Yesterday, it went live and is listing in the apps category of Android 5.0+ devices.