You can do the same thing here. There is no hard requirement that you use Google Play. If the app developers publish their source you can build an apk yourself.
With the upcoming change, we loose this verification when using Google's app store.
Developers can still create key pairs themselves and upload them to Google. So they can still publish their public key if they want and you can be certain that APKs distributed from somewhere other than Play were definitely signed by the developer.