Examine source code of Chess.com Rating Hider

{
  "manifest_version": 2,
  "name": "Chess.com Rating Hider",
  "version": "1.0",
  "description": "Hides ratings on Chess.com",
  "homepage_url": "https://github.com/bomoko/chess_rating_hider",
  "icons": {
    "48": "icons/hiderating-48.png"
  },
  "permissions": [
    "*://www.chess.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://www.chess.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "styles.css"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{880a585f-e25b-4e6f-b623-d7bda32ac501}"
    }
  }
}