Examine source code of Screen Curtain

{
  "name": "Screen Curtain",
  "short_name": "SC",
  "version": "2018.9resigned1",
  "manifest_version": 2,
  "description": "To assist sighted users in testing web pages using a screen reader by simulating blindness..",
  "homepage_url": "http://whatsock.com/training/matrices/screen_curtain.htm",
  "author": "VA by Bryan Garaventa. Extention by Laurence lewis",
  "background": {
    "scripts": [
      "load-sc.js"
    ],
    "persistent": true
  },
  "icons": {
    "16": "icons/icon-16.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "icons/icon-16.png",
      "48": "icons/icon-48.png"
    },
    "default_title": "SC"
  },
  "permissions": [
    "https://*/*",
    "http://*/*",
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{760d2e42-b1d5-477a-a78c-ee30635c69c1}"
    }
  }
}