Background Sync API
Provides one-off and periodic synchronization for Service Workers with an onsync event.
Cookie Store API
An API for reading and modifying cookies. Compared to the existing `document.cookie` method, the API provides a much more modern interface, which can also be used in service workers.
A modern replacement for XMLHttpRequest.
Method that enables applications to take advantage of persistent background processing, including hooks to enable bootstrapping of web applications while offline.
Add to home screen (A2HS)
The ability for a user to "install" a website and use it as if it was a natively installed app. To enable this behaviour, a website must serve a valid Web App Manifest and load it's assets through a [Service Worker](https://caniuse.com/#feat=serviceworkers).