Add-ons/Terminology

WebExtensions/Extensions/Add-ons

As of July 2017, we are moving away from calling extensions built with WebExtensions APIs "WebExtensions", and towards calling them simply "Extensions".

Background

When we first decided to move add-ons to a new API model, we needed a name for it that 1) was searchable 2) was distinguishable from legacy extensions and 3) signals its cross-browser interoperability. “WebExtensions” did all three, and we used it to describe extensions built with this new API.

Now that we’re close to completing the transition and supporting just one API for building extensions, we need to gradually drop the term “WebExtensions”.

Glossary

• Add-on: an umbrella term that describes different types of code that extend Firefox. Mostly used on AMO. Includes extensions, themes, plug-ins, dictionaries, etc.
• Extensions: pieces of code that extend the capabilities of a browser. In Firefox, extensions are a type of add-on.
• Browser extensions: cross-browser extensions implemented using the Browser Extensions standard.
• WebExtensions: a deprecated term that describes a Firefox extension built with WebExtensions APIs. Starting in Firefox 57, only extensions built with WebExtensions APIs will be supported. Therefore, we will start referring to them simply as "extensions".

Usage Guidelines

• “Add-ons” and “Extensions” should not be used interchangeably.
• Copy should say “Cool new extensions” rather than “Cool new WebExtensions”
• For MDN extension documentation, formal cases (like the main title of the page) should say "Browser extensions", and thereafter "extensions" as an informal shorthand

addons.mozilla.org (AMO)

The site where you go to list and download add-ons is "addons.mozilla.org (AMO)" on the first mention, and "AMO" after that.