Examine source code of Chess Notation Helper

{
  "manifest_version": 2,
  "name": "Chess Notation Helper",
  "version": "1.6.0",
  "description": "Highlights chess squares based on notation input during games on Lichess and Chess.com.",
  "permissions": [
    "storage",
    "*://*.lichess.org/*",
    "*://*.chess.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.lichess.org/*",
        "*://*.chess.com/*"
      ],
      "js": [
        "content.js"
      ],
      "css": []
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "chess-notation-helper@mldnq.com",
      "strict_min_version": "58.0"
    }
  }
}