[release-notes/gnome-3-20] developers page - add a first draft for the xdg-app section

[Allan Day <allanday src gnome org>]

commit 2b92037bac1179c2c9686c05b12dfe6d3ff42acb
Author: Allan Day <allanpday gmail com>
Date:   Sat Mar 12 18:32:49 2016 +0000

    developers page - add a first draft for the xdg-app section

 help/C/developers.page |   46 +++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 45 insertions(+), 1 deletions(-)
---
diff --git a/help/C/developers.page b/help/C/developers.page
index 5120d6a..2666055 100644
--- a/help/C/developers.page
+++ b/help/C/developers.page
@@ -65,8 +65,52 @@ give it a try and see how you like it!</p>
   </section>
 
   <section id="xdg-app">
-    <title>XDG App</title>
+    <title>xdg-app</title>
     <media type="image" src="figures/placeholder.png"/>
+    <p><link href="https://wiki.gnome.org/Projects/SandboxedApps";>xdg-app
+    </link> is the new GNOME framework for cross-distro, sandboxed
+    applications. It aims to make it possible to create applications that can
+    be used on different distributions. It also aims to increase security, by
+    exposing as little of the host as possible to the application. 3.20 is a
+    significant moment for this initiative, with a number of core features
+    being released for the first time.</p>
+    <p>The 3.20 release of xdg-app includes tools for building and running
+    bundled applications. A new build tool called xdg-app-builder makes it
+    easy to build apps. Alex Larsson, xdg-app's lead developer, has written a
+    five part tutorial on building apps (<link 
href="https://blogs.gnome.org/alexl/2016/02/19/building-an-xdg-app-part-1/";>part one</link>,
+    <link href="https://blogs.gnome.org/alexl/2016/02/19/building-an-xdg-app-part-2/";>part two</link>,
+    <link href="https://blogs.gnome.org/alexl/2016/02/22/building-an-xdg-app-part-3/";>part three</link>,
+    <link href="https://blogs.gnome.org/alexl/2016/02/23/building-an-xdg-app-part-4/";>part four</link>,
+    <link href="https://blogs.gnome.org/alexl/2016/02/26/building-an-xdg-app-part-5/";>part five</link>).</p>
+    <p>For those who want to try installing and running an xdg-app, a
+    collection of nightly GNOME applications is available to try. In addition
+    to being a great way to try xdg-app, this is also test GNOME applications
+    in development, and demonstrates xdg-app's ability to install multiple
+    different versions of the same application at the same time. For more
+    information,
+    <link href="https://blogs.gnome.org/alexl/2016/02/11/testing-unstable-gnome-using-xdg-app/";>
+    a tutorial is available</link>.</p>
+    <p>Other significant developments in the 3.20 cycle include:</p>
+    <list>
+      <item><p>It is now possible to create and distribute single file
+      application bundles. This is particularly useful for distributing
+      applications using physical media.</p></item>
+      <item><p>xdg-app now has a generic permissions store that can be used to
+      record information about what applications are allowed to do what. This
+      is one of the first steps towards application sandboxing.</p></item>
+      <item><p>Detailed information about the application, such as a
+      description and screenshots, can now be included in an xdg-app bundle,
+      using the cross-desktop AppData/AppStream standard. This can be used by
+      app stores like GNOME Software to provide a rich graphical installation
+      experience.</p></item>
+      <item><p>The GNOME runtimes, which provide the common platform on which
+      applications can depend, have been updated and improved, and are now
+      easier to contribute to. They now include an unstable runtime, which can
+      be used to install nightly applications, or for application development.
+      For details about all the runtimes that are availalbe, see the
+      <link href="https://wiki.gnome.org/Projects/SandboxedApps/Runtimes";>
+      runtimes wiki page</link>.</p></item>
+    </list>
   </section>
 
   <section id="gtk+">