Examine source code of Text Watermark Remover

{
  "manifest_version": 2,
  "name": "Text Watermark Remover",
  "version": "1.1.0",
  "description": "Removes invisible watermark characters on copy.",
  "permissions": [
    "scripting",
    "storage",
    "<all_urls>"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "web_accessible_resources": [
    "inject.js"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "watermark-remover@example.com"
    }
  }
}