E
e.g.
Abbreviation for “for example.”
Enhanced Tracking Protection
Always capitalized. Do not use Tracking Protection or Content Blocking. Internal abbreviation is ETP; do not use ETP in product UI or copy.
One word, lowercase, no hyphen.
Exit
To follow desktop platform conventions, use "Exit" in the application menu in Linux only. Windows is "Quit." MacOS does not have this function from the application menu.
extension
A type of browser add-on. Extension is lowercase when on its own. It can be singular or plural as needed and is always localized. Within Firefox, use “extensions” versus “add-ons.” For example, say “extensions and themes” rather than “add-ons.”
F
Firefox Add-ons
Avoid using. When possible, use "Extensions and themes." Add-ons is capitalized when it follows Firefox, lowercase when on its own, though the O is always lowercase; it can be singular or plural as needed and is always localized. See also the Add-ons Terminology wiki entry.
Firefox Beta
Firefox Beta on the first mention, Beta on subsequent mentions, always capitalized.
Firefox Beta for mobile
“Beta for mobile” is also acceptable, but never “mobile Beta;” mobile is always lowercase.
Firefox browser
Use this to differentiate from another particular Firefox product (Firefox for Android, Firefox iOS, etc.); browser is always lowercase. Do not use this phrase in the product or product branding.
Firefox Developer Edition
Firefox Developer Edition on the first mention, Developer Edition on subsequent mentions, both words always capitalized.
Firefox for Android
Use this in most cases when referring to the mobile browser (see also “Firefox browser”); Android is always capitalized; never “Firefox Android,” “Firefox on Android” or any other variation.
Firefox for iOS
Use this in most cases when referring to the mobile browser (see also “Firefox browser”); never “Firefox iOS,” “Firefox on iOS” or any other variation.
Firefox for desktop
Use this to differentiate from the mobile browsers (see also “Firefox browser”); desktop is always lowercase; never “desktop Firefox” or “Firefox desktop.”
Firefox for mobile
Mobile is always lowercase; never “mobile Firefox” or “Firefox mobile.”
Firefox Focus
The name for our private mobile browser in iOS and Android. Firefox Focus on the first mention, Focus on subsequent mentions, always capitalized.
Firefox Nightly
Firefox Nightly on the first mention, Nightly on subsequent mentions, always capitalized.
Firefox Private
Use to reinforce user's launch experience on a private new tab and dock/taskbar shortcut. Title case. Private should be localized.
Firefox Themes
Themes is capitalized when it follows Firefox, lowercase when on its own; it can be singular or plural as needed and is always localized; formerly “Firefox Personas.” See also the Add-ons Terminology wiki entry.
free
This one is tricky as it means both “without cost” and “without restrictions” in English, though there are separate words for these concepts in many other languages; please be clear when using or avoid.
fullscreen
One word, lowercase, when referring to the view mode of the browser; use “entire screen,” “whole screen” or similar formulation in other cases.