Examine source code of Media Sniffer

{
  "manifest_version": 2,
  "name": "Media Sniffer",
  "version": "2.4.1",
  "description": "Detects video and audio streams loading on the current tab and saves them with one click.",
  "browser_specific_settings": {
    "gecko": {
      "id": "{a0dc3045-fa6b-4861-974c-f40633782902}",
      "strict_min_version": "101.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "icons": {
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "64": "icons/icon64.png",
    "96": "icons/icon96.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "webRequest",
    "downloads",
    "activeTab",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "src/core.js",
      "src/background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_popup": "src/popup.html",
    "default_title": "Media Sniffer",
    "default_icon": {
      "32": "icons/icon32.png",
      "48": "icons/icon48.png",
      "64": "icons/icon64.png",
      "96": "icons/icon96.png",
      "128": "icons/icon128.png"
    }
  }
}