Examine source code of ftvplus for FranceTV

{
  "manifest_version": 2,
  "name": "ftvplus for FranceTV",
  "version": "1.0.6",
  "description": "French Learning Experience for france•tv users - learn French language while you watch TV.",
  "icons": {
    "16": "src/assets/icons/icon16.png",
    "32": "src/assets/icons/icon32.png",
    "48": "src/assets/icons/icon48.png",
    "128": "src/assets/icons/icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "ftvplus@ftvplus.eu",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "browser_action": {
    "default_icon": {
      "16": "src/assets/icons/icon16.png",
      "32": "src/assets/icons/icon32.png",
      "48": "src/assets/icons/icon48.png"
    },
    "default_popup": "popup.html"
  },
  "permissions": [
    "https://ftvplus.eu/*",
    "wss://ftvplus.eu/*",
    "https://www.france.tv/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://www.france.tv/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "injected.js"
  ]
}