Adrien Gat enhanced the thunderbird/thunderbird-l10n repository by implementing French pluralization logic for the attachment removal command, ensuring UI labels accurately reflected the number of attachments for French-speaking users. Using JavaScript and leveraging front end development skills, Adrien migrated the compose localization pipeline to a PluralForm-based framework, addressing Bug 1935334 and improving localization consistency. The work focused on internationalization and localization, unifying pluralization handling across locales and reinforcing locale-specific user experience standards. Although the scope was limited to one feature over a month, the changes contributed to maintainable code and a more accurate, user-friendly interface for localized Thunderbird builds.