Examine source code of Cycle Input Focus Plus

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "description": "__MSG_extensionDescription__",
  "author": "Thomas Henlich",
  "version": "3.0.1",
  "default_locale": "en",
  "applications": {
    "gecko": {
      "id": "{f84230b0-a4a8-11db-b37a-0800200c9a68}",
      "strict_min_version": "66.0"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "commands": {
    "previousInput": {
      "suggested_key": {
        "default": "Ctrl+Alt+X"
      },
      "description": "__MSG_functionPrevious__"
    },
    "nextInput": {
      "suggested_key": {
        "default": "Ctrl+Alt+C"
      },
      "description": "__MSG_functionNext__"
    },
    "firstUserNameInput": {
      "suggested_key": {
        "default": "Ctrl+Alt+U"
      },
      "description": "__MSG_functionFirstLogin__"
    },
    "cyclePWInput": {
      "suggested_key": {
        "default": "Ctrl+Alt+P"
      },
      "description": "__MSG_functionCyclePassword__"
    },
    "cycleUserNameInput": {
      "suggested_key": {
        "default": "Ctrl+Alt+N"
      },
      "description": "__MSG_functionCycleLogin__"
    },
    "firstPWInput": {
      "suggested_key": {
        "default": "Ctrl+Alt+F"
      },
      "description": "__MSG_functionFirstPassword__"
    },
    "firstInput": {
      "suggested_key": {
        "default": "Ctrl+Alt+S"
      },
      "description": "__MSG_functionFirst__"
    }
  },
  "permissions": [
    "activeTab"
  ]
}