Examine source code of DMAddon

{
  "manifest_version": 2,
  "name": "DMAddon",
  "version": "1.0.1resigned1",
  "description": "Change case letter",
  "icons": {
    "16": "icona_16.png",
    "128": "icona_128.png"
  },
  "browser_action": {
    "default_icon": "icona_16.png"
  },
  "permissions": [
    "tabs",
    "activeTab",
    "contextMenus"
  ],
  "background": {
    "scripts": [
      "dmback.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "dmquery.js"
      ]
    }
  ],
  "commands": {
    "upper": {
      "suggested_key": {
        "default": "Alt+1",
        "windows": "Alt+1"
      },
      "description": "Converte in maiuscolo"
    },
    "lower": {
      "suggested_key": {
        "default": "Alt+2",
        "windows": "Alt+2"
      },
      "description": "Converte in minuscolo"
    },
    "sentence": {
      "suggested_key": {
        "default": "Alt+3",
        "windows": "Alt+3"
      },
      "description": "Converte in sentence"
    },
    "title": {
      "suggested_key": {
        "default": "Alt+4",
        "windows": "Alt+4"
      },
      "description": "Converte in title"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{e750bfa4-60a2-4983-863d-9a9e15f18623}"
    }
  }
}