<html lang> does not change to default language

I noticed that the <html lang="en"> tag does not change to the default language I set in Directus. Because of this, browser translators try to translate from the same language to the same language, and the translation becomes very strange and wrong. Many users have auto-translate on in the browser, so it makes the problem worse.

Does anyone know how to make <html lang> match the selected language in Directus?