Google announced they have started to release several apps that sport the new Android Instant Apps feature. This allows Android users to use an Android app, without having to install the app from the Play store.
Google demonstrated it back at Google I/O last year as a way to use Android apps without requiring installation.
Google has allowed a few publishers launch these in the real Android world as a live test. These publishers include BuzzFeed, Wish, Periscope, and Viki. These live tests will allow Google to collect “user feedback and iterating on the product.”
For more details, see the Android developer blog.