re-display the app in grid

data/meson.build

 subdir('icons')
+
+# Metainfo
+metainfo_conf = configuration_data()
+metainfo_conf.set('app-id', application_id)
+metainfo_conf.set('gettext-package', gettext_package)
+metainfo_file = i18n.merge_file (
+  input: configure_file(
+    input: '@0@.metainfo.xml.in.in'.format(base_id),
+    output: '@BASENAME@',
+    configuration: metainfo_conf
+  ),
+  output: '@0@.metainfo.xml'.format(application_id),
+  po_dir: podir,
+  install: true,
+  install_dir: datadir / 'metainfo'
+)
+# Validate metainfo
+if appstream_util.found()
+  test(
+    'validate-metainfo', appstream_util,
+    args: [
+      'validate', '--nonet', metainfo_file.full_path()
+    ]
+  )
+endif
+
 # Desktop file
 desktop_conf = configuration_data()
 desktop_conf.set('icon', application_id)

data/org.gnome.Tour.desktop.in.in

@@ -10,4 +10,3 @@ Keywords=Gnome;GTK;
 Icon=@icon@
 StartupNotify=true
 OnlyShowIn=GNOME;
-NoDisplay=true

data/org.gnome.Tour.metainfo.xml.in.in

+<?xml version="1.0" encoding="UTF-8"?>
+<!-- Bilal Elmoussaoui 2020 <bilal.elmoussaoui@gnome.org> -->
+<component type="desktop-application">
+  <id>@app-id@</id>
+  <metadata_license>CC0</metadata_license>
+  <project_license>GPL-3.0+</project_license>
+  <name>Tour</name>
+  <summary>GNOME Tour and Greeter</summary>
+  <description>
+    <p>A guided tour and greeter for GNOME.</p>
+  </description>
+  <screenshots>
+      <screenshot type="default">
+        <image>https://gitlab.gnome.org/GNOME/gnome-tour/raw/master/data/resources/screenshots/screenshot1.png</image>
+        <caption>Main Window</caption>
+      </screenshot>
+  </screenshots>
+  <url type="homepage">https://gitlab.gnome.org/GNOME/gnome-tour</url>
+  <url type="bugtracker">https://gitlab.gnome.org/GNOME/gnome-tour/issues</url>
+  <url type="donation">http://www.gnome.org/friends/</url>
+  <content_rating type="oars-1.0" />
+  <releases>
+    <release version="3.38.0" date="2020-09-15" />
+    <release version="3.37.92" date="2020-09-08" type="developement" />
+    <release version="3.37.91" date="2020-08-21" type="developement" />
+    <release version="0.0.1" date="2020-03-01" />
+  </releases>
+  <kudos>
+      <!--
+        GNOME Software kudos:
+        https://gitlab.gnome.org/GNOME/gnome-software/blob/master/doc/kudos.md
+      -->
+      <kudo>ModernToolkit</kudo>
+      <kudo>HiDpiIcon</kudo>
+  </kudos>
+  <project_group>GNOME</project_group>
+  <developer_name>The GNOME Project</developer_name>
+  <update_contact>bilal.elmoussaoui@gnome.org</update_contact>
+  <translation type="gettext">@gettext-package@</translation>
+  <launchable type="desktop-id">@app-id@.desktop</launchable>
+</component>

po/POTFILES.in

 data/org.gnome.Tour.desktop.in.in
+data/org.gnome.Tour.metainfo.xml.in.in
 src/widgets/pages/welcome.rs
 src/widgets/paginator.rs
 src/widgets/window.rs