To support internationalization, we might need:

• a lang option (for a project and in front matter), to inform the lang attribute of the document
• a dir option (or lang_dir) for the dir attribute — necessary for right-to-left writing systems (Arabic, Farsi…).
• tracking the lang and dir of each page for the sidebar and search results
• translation files for the few keywords we have (“Search”, “Previous”, “Next“…), maybe using .po files (not sure about what is the current best practice?)
• default locale (to pass to Plot, for example)