The interface stays monolingual
Explorer titles, “Backlinks”, the date in the header — they follow the site-wide locale. For a
fully translated interface: one build per language
(8.2).
The search index covers every language
In a shared build the search finds hits in any language. That cannot be separated per language — again, only through separate builds.
Writing direction is site-wide
dir (right to left) belongs to the whole site in Quartz. The plugin does not change it per page;
for Arabic or Hebrew alongside a Latin-script language a build of its own is needed.
Frontmatter pages have no slug convention
A page whose language comes only from the frontmatter has no computable partner path. Fallback
redirects and link rewriting do not apply to it; the switcher and hreflang do
(2.1).
Never two pages of one language in a group
A contradictory link is skipped and reported, not guessed (3.2).
Three things need JavaScript
The notices, the remembered language choice and localizeDates. Everything else — switcher,
hreflang, redirects — is settled at build time and works without a script.
The plugin translates nothing
It orders, links and points. The text is written by whoever writes the note.