The document discusses developing multilingual apps and localization. It covers internationalization (i18n) and localization (l10n) basics like handling different languages and encodings. It demonstrates marking translatable strings in code and the process of building locales. Localization is defined as implementing a specific language for an already internationalized software by adapting it to a given culture. Steps for localizing free and open source software like building the environment and merging translations are outlined. The document also briefly mentions opportunities for contributing to localization efforts.