Examine source code of Vietnamese Telex

{
  "applications": {
    "gecko": {
      "id": "TypingVietnamese@thoduongluat.com"
    }
  },
  "manifest_version": 2,
  "name": "Vietnamese unicode typing",
  "version": "4.1",
  "description": "Vietnamese unicode typing, danh tieng viet, go tieng viet co dau, đánh tiếng việt, gõ tiếng việt",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "48": "vn19.png",
      "128": "en19.png"
    },
    "default_title": "Typing Vietnamese: off"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "keyevents.js",
        "vnkey.js"
      ],
      "run_at": "document_idle",
      "all_frames": true
    }
  ],
  "permissions": [
    "tabs",
    "<all_urls>",
    "webNavigation",
    "storage"
  ],
  "icons": {
    "128": "icon128.png"
  }
}