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docs/dev.md

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+# Hidden Features
+
+Ok, now they are no longer hidden :).  
+This section contains small setting options that the majority of users do not change or change very rarely and therefore saved the effort of creating an elaborate settings interface.
+
+Create a `dev.json` in your filemanager.
+
+## JSON Properties
+
+The JSON object has the following properties:
+
+| Key | Type | Description | Default |
+| --- | ---- | ----------- | ------- |
+| `bootsound` | string | Uses a custom melodie from the MELODIES folder | standart |
+| `uppercase` | boolean | Print every character in uppercase | true |