Examine source code of review marker

{
  "name": "review marker",
  "version": "1.0",
  "description": "⏵/⏸: {Ctrl: ⏺/ }, {⏺: ⏮/⏭}, {⎚: }",
  "manifest_version": 2,
  "icons": {
    "32": "暗_icon.svg",
    "64": "亮_icon.svg"
  },
  "permissions": [
    "activeTab",
    "file://*/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "theme_icons": [
      {
        "light": "亮_icon.svg",
        "dark": "暗_icon.svg",
        "size": 32
      }
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{171a169c-5c2a-4265-9b5a-0b160e0a9429}"
    }
  }
}