--- /dev/null
+{#
+/**
+ * @file
+ * Theme override for rendering book outlines within a block.
+ *
+ * This template is used only when the block is configured to "show block on all
+ * pages", which presents multiple independent books on all pages.
+ *
+ * Available variables:
+ * - book_menus: Book outlines.
+ * - id: The parent book ID.
+ * - title: The parent book title.
+ * - menu: The top-level book links.
+ *
+ * @see template_preprocess_book_all_books_block()
+ */
+#}
+{% for book in book_menus %}
+ <nav role="navigation" aria-label="{% trans %}Book outline for {{ book.title }}{% endtrans %}">
+ {{ book.menu }}
+ </nav>
+{% endfor %}