Examine source code of Save Tab Image

{
  "applications": {
    "gecko": {
      "strict_min_version": "52.0",
      "id": "{e9efbe17-814a-43e3-9f22-e62b15920b7d}"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "SaveImage.svg",
    "default_title": "Save Tab Image"
  },
  "icons": {
    "48": "SaveImage.svg",
    "96": "SaveImage.svg"
  },
  "description": "Save the image opened on the tab.",
  "manifest_version": 2,
  "name": "Save Tab Image",
  "permissions": [
    "tabs",
    "downloads",
    "notifications"
  ],
  "version": "1.2resigned1"
}