Examine source code of Image Format Saver

{
  "manifest_version": 2,
  "name": "Image Format Saver",
  "version": "2.9.3.5",
  "description": "Saves any picture in the format you actually need, with a quality slider for JPEG.",
  "browser_specific_settings": {
    "gecko": {
      "id": "{c05fa968-6279-446a-9e9f-0c977bb0aa5e}",
      "strict_min_version": "101.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "icons": {
    "32": "assets/icon32.png",
    "48": "assets/icon48.png",
    "64": "assets/icon64.png",
    "96": "assets/icon96.png",
    "128": "assets/icon128.png"
  },
  "permissions": [
    "contextMenus",
    "downloads",
    "storage",
    "activeTab",
    "notifications",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "app/core.js",
      "app/background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_popup": "app/popup.html",
    "default_title": "Image Format Saver",
    "default_icon": {
      "32": "assets/icon32.png",
      "48": "assets/icon48.png",
      "64": "assets/icon64.png",
      "96": "assets/icon96.png",
      "128": "assets/icon128.png"
    }
  }
}