+This will update the submodule to the HEAD of master branch repository.
+
+You could just want to update at a specified repository tag or branch or commit
+, here are the method to do so:
+
+```bash
+cd conf.d/app-templates
+# Choose one of the following depending what you want
+git checkout <tag_name>
+git checkout --detach <branch_name>
+git checkout --detach <commit_id>
+# Then commit
+cd ../..
+git commit -s conf.d/app-templates
+```
+
+### Build a widget
+
+## config.xml.in file
+
+To build a widget you need a _config.xml_ file describing what is your apps and
+how Application Framework would launch it. This repo provide a simple default
+file _config.xml.in_ that should work for simple application without
+interactions with others bindings.
+
+It is recommended that you use the sample one which is more complete. You can
+find it at the same location under the name _config.xml.in.sample_ (stunning
+isn't it). Just copy the sample file to your _conf.d/wgt_ directory and name it
+_config.xml.in_, then edit it to fit your needs.
+
+> ***CAUTION*** : The default file is only meant to be use for a
+> simple widget app, more complicated ones which needed to export
+> their api, or ship several app in one widget need to use the provided
+> _config.xml.in.sample_ which had all new Application Framework
+> features explained and examples.
+
+## Using cmake template macros
+
+To leverage all cmake templates features, you have to specify ***properties***
+on your targets. Some macros will not works without specifying which is the
+target type.
+
+As the type is not always specified for some custom targets, like an ***HTML5***
+application, macros make the difference using ***LABELS*** property.
+
+Choose between:
+
+- **BINDING**: Shared library that be loaded by the AGL Application Framework
+- **BINDINGV2**: Shared library that be loaded by the AGL Application Framework
+ This has to be accompagnied with a JSON file named like the
+ *${OUTPUT_NAME}-apidef* of the target that describe the API with OpenAPI
+ syntax (e.g: *mybinding-apidef*).
+ Or Alternatively, you can choose the name, without the extension, using macro
+ **set_openapi_filename**. If you use C++, you have to set **PROJECT_LANGUAGES**
+ to *CXX*.
+- **BINDINGV3**: Shared library that be loaded by the AGL Application Framework
+ This has to be accompagnied with a JSON file named like the
+ *${OUTPUT_NAME}-apidef* of the target that describe the API with OpenAPI
+ syntax (e.g: *mybinding-apidef*).
+ Or Alternatively, you can choose the name, without the extension, using macro
+ **set_openapi_filename**. If you use C++, you have to set **PROJECT_LANGUAGES**
+ to *CXX*.
+- **PLUGIN**: Shared library are meant to be used as a binding plugin. A binding
+ would load it as a plugin to extend its functionnalities. It should be named
+ with a special extension that you choose with SUFFIX cmake target property or
+ it'd be **.ctlso** by default.
+- **HTDOCS**: Root directory of a web app. This target has to build its
+ directory and puts its files in the ${CMAKE_CURRENT_BINARY_DIR}/${TARGET_NAME}
+- **DATA**: Resources used by your application. This target has to build its
+ directory and puts its files in the ${CMAKE_CURRENT_BINARY_DIR}/${TARGET_NAME}
+- **EXECUTABLE**: Entry point of your application executed by the AGL
+ Application Framework
+- **LIBRARY**: An external 3rd party library bundled with the binding for its
+ own purpose because platform doesn't provide it.
+- **BINDING-CONFIG**: Any files used as configuration by your binding.
+
+Optional **LABELS** are available to define which resources type your test
+materials are:
+
+- **TEST-CONFIG**: JSON configuration files that will be used by the afb-test
+ binding to know how to execute tests.
+- **TEST-DATA**: Resources used to test your binding. It is at least your test
+ plan and also could be fixtures and any files needed by your tests. These files
+ will appear in a separate test widget.
+- **TEST-PLUGIN**: Shared library meant to be used as a binding
+ plugin. Binding would load it as a plugin to extend its functionalities. It
+ should be named with a special extension that you choose with SUFFIX cmake
+ target property or it'd be **.ctlso** by default.
+- **TEST-HTDOCS**: Root directory of a web app. This target has to build its
+ directory and put its files in the ${CMAKE_CURRENT_BINARY_DIR}/${TARGET_NAME}
+- **TEST-EXECUTABLE**: Entry point of your application executed by the AGL
+ Application Framework
+- **TEST-LIBRARY**: An external 3rd party library bundled with the binding for its
+ own use in case the platform doesn't provide it.
+
+Here is a mapping between LABELS and directories where files will be placed in
+the widget:
+
+- **EXECUTABLE** : \<wgtrootdir\>/bin
+- **BINDING-CONFIG** : \<wgtrootdir\>/etc
+- **BINDING** | **BINDINGV2** | **BINDINGV3** | **LIBRARY** : \<wgtrootdir\>/lib
+- **PLUGIN** : \<wgtrootdir\>/lib/plugins
+- **HTDOCS** : \<wgtrootdir\>/htdocs
+- **BINDING-DATA** : \<wgtrootdir\>/var
+- **DATA** : \<wgtrootdir\>/var
+
+And about test dedicated **LABELS**:
+
+- **TEST-EXECUTABLE** : \<wgtrootdir\>/bin
+- **TEST-CONFIG** : \<TESTwgtrootdir\>/etc
+- **TEST-PLUGIN** : \<wgtrootdir\>/lib/plugins
+- **TEST-HTDOCS** : \<wgtrootdir\>/htdocs
+- **TEST-DATA** : \<TESTwgtrootdir\>/var
+
+> **TIP** you should use the prefix _afb-_ with your **BINDING* targets which
+> stand for **Application Framework Binding**.
+
+Example:
+
+```cmake
+SET_TARGET_PROPERTIES(${TARGET_NAME} PROPERTIES
+ LABELS "HTDOCS"
+ OUTPUT_NAME dist.prod
+ )
+```
+
+> **NOTE**: You doesn't need to specify an **INSTALL** command for these
+> targets. This is already handle by template and will be installed in the
+> following path : **${CMAKE_INSTALL_PREFIX}/${PROJECT_NAME}**
+
+> **NOTE**: if you want to set and use `rpath` with your target you should use
+> and set the target property `INSTALL_RPATH`.
+
+## Add external 3rd party library
+
+### Build, link and ship external library with the project
+
+You could need to include an external library that isn't shipped in the
+platform. Then you have to bundle the required library in the `lib` widget
+directory.
+
+Templates includes some facilities to help you to do so. Classic way to do so
+is to declare as many CMake ExternalProject as library you need.
+
+An ExternalProject is a special CMake module that let you define how to:
+download, update, patch, configure, build and install an external project. It
+doesn't have to be a CMake project and custom step could be added for special
+needs using ExternalProject step. More informations on CMake [ExternalProject
+documentation site](https://cmake.org/cmake/help/v3.5/module/ExternalProject.html?highlight=externalproject).
+
+Example to include `mxml` library for [unicens2-binding](https://github.com/iotbzh/unicens2-binding)
+project:
+
+```cmake
+set(MXML external-mxml)
+set(MXML_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/mxml)
+ExternalProject_Add(${MXML}
+ GIT_REPOSITORY https://github.com/michaelrsweet/mxml.git
+ GIT_TAG release-2.10
+ SOURCE_DIR ${MXML_SOURCE_DIR}
+ CONFIGURE_COMMAND ./configure --build x86_64 --host aarch64
+ BUILD_COMMAND make libmxml.so.1.5
+ BUILD_IN_SOURCE 1
+ INSTALL_COMMAND ""
+)
+
+PROJECT_TARGET_ADD(mxml)
+
+add_library(${TARGET_NAME} SHARED IMPORTED GLOBAL)
+
+SET_TARGET_PROPERTIES(${TARGET_NAME} PROPERTIES
+ LABELS LIBRARY
+ IMPORTED_LOCATION ${MXML_SOURCE_DIR}/libmxml.so.1
+ INTERFACE_INCLUDE_DIRECTORIES ${MXML_SOURCE_DIR}
+)
+
+add_dependencies(${TARGET_NAME} ${MXML})
+```
+
+Here we define an external project that drive the build of the library then we
+define new CMake target of type **IMPORTED**. Meaning that this target hasn't
+been built using CMake but is available at the location defined in the target
+property *IMPORTED_LOCATION*.
+
+You could want to build the library as *SHARED* or *STATIC* depending on your needs
+and goals. Then you only have to modify the external project configure step and change
+filename used by **IMPORTED** library target defined after external project.
+
+Then target *LABELS* property is set to **LIBRARY** to ship it in the widget.
+
+Unicens project also need some header from this library, so we use the target
+property *INTERFACE_INCLUDE_DIRECTORIES*. Setting that when another target link
+to that imported target, it can access to the include directories.
+
+We bound the target to the external project using a CMake dependency at last.
+
+Then this target could be use like any other CMake target and be linked etc.
+
+### Only link and ship external library with the project
+
+If you already have a binary version of the library that you want to use and you
+can't or don't want to build the library then you only have to add an **IMPORTED**
+library target.