Examine source code of Stigma

{
  "name": "Stigma",
  "description": "Easily add comments to any website. Perfect for developers, designers and project managers.",
  "version": "1.0.3",
  "manifest_version": 2,
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "exclude_matches": [
        "http://f.stigma.dev/*",
        "https://f.stigma.dev/*",
        "https://i.stigma.dev/*",
        "https://i.stigma.dev/*",
        "https://www.stigma.dev/*",
        "https://stigma.dev/*"
      ],
      "js": [
        "/static/js/content.js"
      ],
      "all_frames": false,
      "run_at": "document_start"
    }
  ],
  "icons": {
    "16": "icon16.png",
    "32": "icon32.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "web_accessible_resources": [
    "/static/*",
    "/misunderstanding.png",
    "/camera-shutter.wav",
    "https://i.stigma.dev/*",
    "https://f.stigma.dev/*"
  ],
  "permissions": [
    "tabs",
    "storage",
    "webRequest",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "/static/js/background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "action-off16.png",
      "24": "action-off24.png",
      "32": "action-off32.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f74c01b8-89ed-4325-a835-18d89d8d1e71}"
    }
  }
}