Examine source code of unMute

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "version": "1.0.1resigned1",
  "browser_specific_settings": {
    "gecko": {
      "id": "unMute@example.org"
    }
  },
  "default_locale": "en",
  "description": "__MSG_extensionDescription__",
  "icons": {
    "16": "resources/icon/icon16.png",
    "32": "resources/icon/icon32.png",
    "48": "resources/icon/icon48.png",
    "128": "resources/icon/icon128.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "resources/icon/icon16.png",
      "32": "resources/icon/icon32.png",
      "48": "resources/icon/icon48.png",
      "128": "resources/icon/icon128.png"
    }
  },
  "background": {
    "scripts": [
      "src/js/background.js"
    ]
  },
  "commands": {
    "mute_current_tab": {
      "suggested_key": {
        "default": "Alt+M"
      },
      "description": "__MSG_command_mute_current_tab__"
    },
    "auto_mute": {
      "suggested_key": {
        "default": "Alt+0"
      },
      "description": "__MSG_command_auto_mute__"
    },
    "auto_recent": {
      "suggested_key": {
        "default": "Alt+Shift+0"
      },
      "description": "__MSG_command_auto_recent__"
    },
    "mute_all_tabs": {
      "suggested_key": {
        "default": "Alt+A"
      },
      "description": "__MSG_command_mute_all_tabs__"
    },
    "toggle_all_tabs": {
      "suggested_key": {
        "default": "Alt+Shift+M"
      },
      "description": "__MSG_command_toggle_all_tabs__"
    }
  },
  "options_ui": {
    "page": "src/html/options.html",
    "browser_style": true
  },
  "permissions": [
    "tabs",
    "activeTab",
    "storage",
    "contextMenus"
  ]
}