Source

liquid_feedback_frontend / app / main / _filter / 20_session.lua

Full commit
if cgi.cookies.liquid_feedback_session then
  app.session = Session:by_ident(cgi.cookies.liquid_feedback_session)
end
if not app.session then
  app.session = Session:new()
  request.set_cookie{
    name = "liquid_feedback_session",
    value = app.session.ident
  }
end

request.set_csrf_secret(app.session.additional_secret)

locale.set{lang = app.session.lang or config.default_lang or "en"}

execute.inner()