Examine source code of Simple Screenshot v2

{
  "manifest_version": 2,
  "name": "Simple Screenshot Tool",
  "version": "1.0",
  "description": "Capture and annotate screenshots within the browser.",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "activeTab",
    "downloads"
  ],
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{195334ff-7e2e-491c-bd61-bbd47d626cf0}"
    }
  }
}