Use the browser.browserSettings API to control global settings of the browser.

Permissions: browserSettings

Not allowed in: Content scripts, Devtools pages

colorManagement
ColorManagementMode
ContextMenuMouseEvent
ImageAnimationBehavior
allowPopupsForUserEvents
cacheEnabled
closeTabsByDoubleClick
contextMenuShowEvent
ftpProtocolEnabled
homepageOverride
imageAnimationBehavior
newTabPageOverride
newTabPosition
openBookmarksInNewTabs
openSearchResultsInNewTabs
openUrlbarResultsInNewTabs
overrideContentColorScheme
overrideDocumentColors
useDocumentFonts
webNotificationsDisabled
zoomFullPage
zoomSiteSpecific
ColorManagementMode: "off" | "full" | "tagged_only"

Color management mode.

ContextMenuMouseEvent: "mouseup" | "mousedown"

After which mouse event context menus should popup.

ImageAnimationBehavior: "normal" | "none" | "once"

How images should be animated in the browser.

allowPopupsForUserEvents: Setting

Allows or disallows pop-up windows from opening in response to user events.

cacheEnabled: Setting

Enables or disables the browser cache.

closeTabsByDoubleClick: Setting

This boolean setting controls whether the selected tab can be closed with a double click.

contextMenuShowEvent: Setting

Controls after which mouse event context menus popup. This setting's value is of type ContextMenuMouseEvent, which has possible values of mouseup and mousedown.

ftpProtocolEnabled: Setting

Returns whether the FTP protocol is enabled. Read-only.

FTP support was removed from Firefox in bug 1574475

homepageOverride: Setting

Returns the value of the overridden home page. Read-only.

imageAnimationBehavior: Setting

Controls the behaviour of image animation in the browser. This setting's value is of type ImageAnimationBehavior, defaulting to normal.

newTabPageOverride: Setting

Returns the value of the overridden new tab page. Read-only.

newTabPosition: Setting

Controls where new tabs are opened. afterCurrent will open all new tabs next to the current tab, relatedAfterCurrent will open only related tabs next to the current tab, and atEnd will open all tabs at the end of the tab strip. The default is relatedAfterCurrent.

openBookmarksInNewTabs: Setting

This boolean setting controls whether bookmarks are opened in the current tab or in a new tab.

openSearchResultsInNewTabs: Setting

This boolean setting controls whether search results are opened in the current tab or in a new tab.

openUrlbarResultsInNewTabs: Setting

This boolean setting controls whether urlbar results are opened in the current tab or in a new tab.

overrideContentColorScheme: Setting

This setting controls whether a light or dark color scheme overrides the page's preferred color scheme.

overrideDocumentColors: Setting

This setting controls whether the user-chosen colors override the page's colors.

useDocumentFonts: Setting

This setting controls whether the document's fonts are used.

webNotificationsDisabled: Setting

Disables webAPI notifications.

zoomFullPage: Setting

This boolean setting controls whether zoom is applied to the full page or to text only.

zoomSiteSpecific: Setting

This boolean setting controls whether zoom is applied on a per-site basis or to the current tab only. If privacy.resistFingerprinting is true, this setting has no effect and zoom is applied to the current tab only.