App Browser Guide¶

This page describes features of the app browser (the custom Firefox installation that runs installed web apps). Most existing Firefox features are available, although with some differences, but the project also adds some new features to make experience better.

Using the App Browser¶

Using Web Apps¶

When you launch a web app (for example, from the system start/app menu), it will automatically open in the app browser. You don't have to do anything special.

By default, when you navigate to the website that is outside the scope of the current web app, the browser will display a disabled address bar with the current URL. This is used for security reasons to ensure that you know you are not in the original web app anymore. This behavior can be changed in the settings (see below for configuration options).

Using Firefox Features¶

Most built-in standard Firefox features can still be accessed, including support for addons. The main differences are that the main Firefox menu button and default widgets have been moved to the titlebar, and that tabs and address bar are hidden by default.

Features that require entering URL directly (such as about:config) can be used by navigating to the URL (see below for the URL input instructions).

Addons can be installed from the built-in Firefox addon manager (which can be accessed with a keyboard shortcut or from the Firefox menu) or by manually navigating to the Addon Store URL (see below for the URL input instructions).

Navigating to Arbitrary URLs¶

You can open a basic URL input popup by pressing F6, Ctrl+L or Alt+D. You can navigate to any URL, including built-in ones such as about:config. Please keep in mind that auto-completion and search functionality are not supported.

The app browser provides some additional toolbar widgets that can be used for additional functionalities or provide an alternative to existing, now hidden widgets. Some of them are enabled by default, others can be enabled in the Firefox customize page.

Site Information¶

Enabled by default, cannot be disabled. Provides site information that would otherwise be displayed in the address bar.

Site Permissions¶

Enabled by default, cannot be disabled. Provides a list of permissions granted to the current site that would otherwise be displayed in the address bar.

Site Notification¶

Enabled by default, cannot be disabled. Provides access to popups by sites requesting additional permissions.

Tracking Protection¶

Enabled by default. Provides access to tracking protection popup that would otherwise be accessible from the address bar.

Toggle Sound¶

Enabled by default. Provides support to toggle the page sound that would otherwise be possible from the tab icon.

Reader View¶

Enables or disables the reader view/mode for the current page.

Copy Link¶

Copies the current URL to the clipboard.

Shares the current URL using the system sharing functionality.

Send to Device¶

Sends the current URL to another device using Firefox Account.

Open in Browser¶

Opens the current URL in a default system browser.

Additional Keyboard Shortcuts¶

`Ctrl`+`Shift`+`N`¶

Opens a new window in a default system browser.

`Ctrl`+`Alt`¶

Toggles the icon bar (if hiding is enabled in the settings).

Open Link in Default Browser¶

Opens the link in a default system browser. Displayed only when clicking on links.

Configuration Options¶

Tip

These settings can be accessed in the same place as standard Firefox settings in the app browser: In the web app window, click on the hamburger menu near the top right corner and open settings. Alternatively, they can also be accessed from about:config.

Tip

You may need to restart the app browser for some configuration options to take effect.

Allow web apps to override a theme (titlebar) color¶

Determines whether the web apps can override a theme (titlebar) color of the window.

On most systems, it will correctly set the theme color to the color specified in the manifest. However, it may cause problems on some Linux DEs, so you may need to disable it.

Preference name: firefoxpwa.sitesSetThemeColor
Default value: true

Allow web apps to override a background (window) color¶

Determines whether the web apps can override a background color of the window.

On most websites, it will correctly set the background color to the color specified in the manifest. However, it may cause problems on some websites, so you may need to disable it.

Preference name: firefoxpwa.sitesSetBackgroundColor
Default value: true

Allow web apps to dynamically change a theme color¶

Determines whether the web apps can dynamically change a theme color using meta tags.

Preference name: firefoxpwa.dynamicThemeColor
Default value: true

Change the window title based on the web app's title¶

Determines whether the window title is dynamically changed to the web app's title.

Preference name: firefoxpwa.dynamicWindowTitle
Default value: true

Change the window icon based on the web app's icon¶

Determines whether the window icon is dynamically changed to the web app's icon.

Preference name: firefoxpwa.dynamicWindowIcon
Default value: true

Always use native window controls (Linux-only)¶

Determines whether native window controls should be displayed even when using Firefox themes. Only displayed and used on Linux with CSD enabled.

Preference name: firefoxpwa.alwaysUseNativeWindowControls
Default value: false

Open out-of-scope URLs in a default browser¶

Determines whether out-of-scope URLs should be opened in a default browser.

Enabling this option will automatically close the web app window and open any out-of-scope URLs in a default system browser. This may cause problems on some websites, especially ones that use SSO (such as Google, YouTube, Spotify, Outlook.com). In such cases, it is recommended to use it in combination with domains always allowed to be opened in the app browser.

Preference name: firefoxpwa.openOutOfScopeInDefaultBrowser
Default value: false

Domains always allowed to be opened in the app browser¶

Determines which domains should always be opened in the app browser.

This option can be used to always load a specific domain in the app browser, even if the URL is out-of-scope. This can be useful for websites that do not work properly with the previous option enabled. It only has an effect when that option is also enabled.

The value should be a comma-separated list of domains (without protocol and path). A wildcard * can to match zero or more characters. A wildcard can be escaped by using \*.

Preference name: firefoxpwa.allowedDomains
Default value: ""

Tip

You can check a list of recommended values for some popular websites.

Show browser tabs and enable using multi-tabbed web apps¶

Determines whether the tabs mode is enabled.

Enabling this option will cause the app browser to display tabs, similar to a normal browser, but without the address bar. It will also re-enable new tab keyboard shortcuts and menu items, and replace the new tab page with a web app start URL. This will allow you to use multiple tabs of the same web app in the same window.

Preference name: firefoxpwa.enableTabsMode
Default value: false

Changing the links target¶

When opening a link that should normally open in a new window or tab:

0 - Do not change link behavior (not recommended)

1 - Force links into the current tab (default)

2 - Force links into a new window

3 - Force links into a new tab

Determines whether _blank links target is forced into the current tab or a new window.

Preference name: firefoxpwa.linksTarget
Default value: 1

Changing the launch type¶

When launching a web app that is already opened:

0 - Open web app in a new window (default)

1 - Open web app in a new tab

2 - Replace the existing tab

3 - Focus the existing window

Determines what happens when a web app is launched if the same web app is already opened.

Preference name: firefoxpwa.launchType
Default value: 0

Changing the address bar¶

Display the address bar:

0 - Display the address bar when out-of-scope (default)

1 - Never display the address bar

2 - Always display the address bar

Determines whether the address bar is displayed only when out-of-scope, always, or never.

Preference name: firefoxpwa.displayUrlBar
Default value: 0

Allowing hiding the icon bar¶

Warning

This is a hidden, about:config-only option. It is only meant for advanced users with a tiling window manager, and can cause problems otherwise. When the icon bar is hidden, you will not be able to access Firefox icons and menus.

Warning

When the icon bar is hidden, popups for installing extensions, granting site permissions and others will not work. Before doing actions that open popups, you need to temporarily enable the icon bar.

Determines whether hiding the icon bar is allowed and displays an option in the customize page.

This does not hide the icon bar on its own. It only adds an entry to the "toolbars" menu in the Firefox customize page that allows you to hide the icon bar. To temporarily display the icon bar, use the Ctrl+Alt keyboard shortcut. To permanently enable it, go to the customize page, uncheck the icon bar entry in the menu and check it again.

Preference name: firefoxpwa.enableHidingIconBar
Default value: false

Note

When the tabs mode is enabled, the "icon bar" is renamed to the "tabs bar" in the customize page menu. The preference name and other functionalities still remain the same.

Disabling keyboard shortcuts¶

Determines whether specific shortcuts are enabled or not.

Close tab (Ctrl+W)
Close window (Ctrl+Shift+W)
Quit application (Ctrl+Shift+Q)
Private browsing (Ctrl+Shift+P)

All shortcuts are enabled by default.