A "web app" or Progressive Web App (PWA) is a version of a website that is installed on your system as a browser-based application, offering a native "app-like" experience for that site. It can be run independently from the browser and may include additional functionality (such as offline viewing), depending on the site that is installed. 

Installing a web app

Web apps can typically be installed in two different ways. Sites that can be installed as an app on your device will display the "Install" icon in the address bar when you visit the site in the browser:

Clicking on this icon in the address bar will prompt you to confirm that you'd like to install the site as an app on your device:

Once installed, the app will relaunch as a web app, displaying in it's own window, isolated from your main browser window and tabs. A shortcut for this app will also be added to your desktop (or wherever you choose to move the shortcut for this app on your device), which can be launched and used separately from the main browser.

Alternatively, web apps can be installed by visiting the site, clicking on the Main menu, then selecting Save and Share --> Install [app]...

Managing web apps in Brave

To view or manage your installed apps, launch Brave and go to brave://apps or click the main menu, then navigate to More tools --> Show apps. Here, you can see a list of any sites you've installed as apps through the browser. You can also right-click on any installed app and adjust individual settings for each app by selecting App settings from the context menu:

Uninstalling an app

Apps can be uninstalled by clicking the menu icon in the app window, then selecting Uninstall app. This can also be done from the brave://apps page by right-clicking on the app icon.