The shared LiveView of a live.ex: one LiveView owns every page in its folder and below.

Switching between those pages is a <.link patch>: the same process keeps its state, and handle_params/3 runs with the new URL. The route's live action is the page module, so by default this LiveView renders the current page's render/1 with its own assigns, inside the page's layouts.

# app/settings/live.ex  →  owns /settings/profile and /settings/security
defmodule MyAppWeb.SettingsLive do
  use MyAppWeb, :live_view
  use Xenia.Live

  def mount(_params, _session, socket), do: {:ok, assign(socket, user: load_user())}

  def handle_params(_params, _uri, socket), do: {:noreply, socket}
end

# app/settings/profile/page.ex
defmodule MyAppWeb.ProfilePage do
  use MyAppWeb, :html

  def render(assigns), do: ~H"<h1>{@user.name}</h1>"
end

Define render/1 yourself to put shared markup around the page; render the page with Xenia.Live.page/1:

def render(assigns) do
  ~H"""
  <nav>...tabs...</nav>
  {Xenia.Live.page(assigns)}
  """
end

The owner handles every event and message; a page's own LiveView callbacks don't run under it. Layouts' on_mount hooks run once, when the owner mounts, so a layout.ex below the live.ex can't declare on_mount: patching to its pages wouldn't run them. xenia_routes rejects that at compile time.