Localization is important for browser extensions because it allows the extension interface to support multiple languages. Localization involves translating the user interface, documentation, and code of an extension so that it can communicate effectively with users speaking different languages. It requires specifying the locale in code, using localized string bundles and files, and tools to help automate and check the translation process.

1. Extension development: LOCALIZATION MATTERS

2. Why does localization matter? English is not the only language on Earth Language is identity Language is communication UI consistency

3. Have your language interface: a touch of Mozilla Magic Automatic language switching general.useragent.locale Quick Locale Switcher

4. Under the hood... How does it work? Locale path in the chrome.manifest Doctype path for xul files Stringbundles for javascript files Locale folder and files

5. Localization Basics From .XUL strings to DTD entities From .JS strings to properties keys

6. More tricks for Extension Localization Have your description localized Have your help.html localized Don't forget accesskeys Variables and placeholders XML-embedded javascript Metadata localizing with Gecko 1.9

7. Tools for Extension Localization Manual process with your text editor BOM sucks UTF-8 rulezzz Semi-automatic process: Externalize extension