* **[browser-state](https://github.com/mozilla-mobile/firefox-android/tree/main/android-components/components/browser/state)** - Representing the state of the browser (_"What tabs are opened?"_, _"What URLs are they pointing to?"_)
* **browser-engine** - The browser engine that transforms web pages into an interactive visual representation. The _browser-engine_ component comes in multiple flavors. We are supporting [Android's WebView](https://github.com/mozilla-mobile/firefox-android/tree/main/android-components/components/browser/engine-system) (limited feature set) and **GeckoView** ([Release](https://github.com/mozilla-mobile/firefox-android/tree/main/android-components/components/browser/engine-gecko), [Beta](https://github.com/mozilla-mobile/firefox-android/tree/main/android-components/components/browser/engine-gecko-beta) and [Nightly](https://github.com/mozilla-mobile/firefox-android/tree/main/android-components/components/browser/engine-gecko-nightly) channels) currently. The actual implementation is hidden behind [generic interfaces](https://github.com/mozilla-mobile/firefox-android/tree/main/android-components/components/concept) so that apps can build against multiple engines (e.g. based on product flavor) and so that other components work seamlessly with all implementations.
Other high-level browser components may depend on those core components.
### Building blocks
The following components offer customizable building blocks for browser apps: