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+## Manifest
+The `manifest.json` file defines the app's constants, a bunch of values that YunoHost needs to identify the app and install it correctly. It looks like this:
+```json
+{
+    "name": "Roundcube",
+    "id": "roundcube",
+    "description": {
+        "en": "Open Source Webmail software",
+        "fr": "Webmail Open Source"
+    },
+    "license": "free",
+    "maintainer": {
+        "name": "kload",
+        "email": "kload@kload.fr",
+        "url": "http://kload.fr"
+    },
+    "multi_instance": "true",
+    "arguments": {
+        "install" : [
+            {
+                "name": "domain",
+                "ask": {
+                    "en": "Choose a domain for Roundcube"
+                },
+                "example": "domain.org"
+            },
+            {
+                "name": "path",
+                "ask": {
+                    "en": "Choose a path for Roundcube"
+                },
+                "example": "/webmail",
+                "default": "/webmail"
+            }
+        ]
+    }
+}
+```
+
+* **name**: the app name. It does not have to be unique, but it should be, since it is the name shown to all the YunoHost administrators in the app list.
+
+* **id**: the unique ID of the app. You have to ensure that this ID is unique before submit an app integration request.
+
+* **description**: the complete description of the app. You can make it as detailed as you feel it should be. Only `en` is required right now, but you can translate the description by prepending the locale prefix.
+
+* **license**: software license type: `free` or `non-free`. Be careful to not confuse with package license which must be put in `LICENSE` file.
+
+* **maintainer**: informations about the app maintainer.
+
+* **multi_instance**: this defines your app's ability to be installed multiple times. When YunoHost tries to install a second instance of the app, it will replace the `id` in the scripts by an `id__2`. It means that, if you want to be `multi_instance`, you have to put all the identifiers in the scripts. 
+<br><br>**E.g.** in the roundcube script, database is called `roundcube`, the install directory `roundcube` and the Nginx configuration `roundcube`. This way, the second instance of roundcube will not conflict with the first one, and will be installed in the `roundcube__2` database, in the `roundcube__2`directory, and with the `roundcube__2` Nginx configuration.
+
+* **arguments**: the settings for the YunoHost's administrator to enter at installation. You have to set a `name` (for argument identification), and a question in `ask` (at least in `en`) that you can translate like the description above. You can also set a `default` value and an `example` to help administrator to fill the input.
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