Dictionaries are fetched the first time a word in their language is
checked, and text no run tags counts as the browser's language. The site
offers en_US, en_GB, de_DE, fr_FR, es_ES, pt_BR, pt_PT, it_IT, nl_NL,
sv_SE and ru_RU from nixpkgs' Hunspell packages, converted to UTF-8 and
gzipped, each with its readme and its licences' texts; a row in
release_web.py's DICTIONARIES adds another. A bare pt picks pt_BR, as
Windows does.

Assisted-by: claude-opus-5.5