добавил манифест

src/layouts/base.njk

@@ -6,6 +6,7 @@
         <title>{{ title or metadata.title }}</title>
         <meta name="description" content="{{ description or metadata.description }}">
         <meta name="generator" content="{{ eleventy.generator }}">
+        <link rel="manifest" href="/manifest.json">
         <link rel="stylesheet" href="/css/index.css">
         {% favicon 'src/images/favicon.svg' %}
     </head>

src/pages/manifset.11tydata.js

@@ -0,0 +1,3 @@
+module.exports = {
+  permalink: '/manifest.json'
+}

src/pages/manifset.njk

@@ -0,0 +1,9 @@
+{
+  "name": "{{ metadata.title }}",
+  "lang": "ru",
+  "start_url": "/",
+  "display": "standalone",
+  "background_color": "#fff",
+  "description": "Вики с различными полезными статьями",
+  "icons": {% manifest_icons 'src/images/favicon.svg', 48, 72, 96, 144, 148 %}
+}