Google Authenticator is one of many two-factor authentication apps available for Android. While Google's attention is more focused on phone login prompts, Authenticator remains a popular choice for having all your 2FA codes for all your accounts in one place. The app has now been updated to v5.0, with a few useful additions in store.
The first new feature is experimental support for USB security keys (FIDO U2F) in Chrome. In other words, once you install the update, you should be able to use Yubikeys and similar devices to login to websites through Chrome (as well as Chrome Custom Tabs/WebViews). I'm not entirely sure why this needed to be part of Google Authenticator, instead of being part of Chrome. I also can't test it, because I don't own a Yubikey, but it appears to work for other people:
Yeah, I've signed into GitHub/Google with my YubiKey Neo in Chrome for Android and a WebView
— David Cook (@divergentdave) September 27, 2017
Another new feature is the ability to hold down on a code to copy it, instead of holding down on it and having to press the Copy button. This is especially useful when you're trying to copy a code from your phone to another app. Finally, the changelog says that Authenticator's app preferences "will be enabled for backup and restore," but I'm guessing that doesn't mean 2FA codes.
Google Authenticator 5.0 should already be rolled out to everyone, but just in case it hasn't reached you, you can also download it from APKMirror.