Examine source code of Show screen reader text

{
  "manifest_version": 2,
  "name": "Show screen reader text",
  "short_name": "Show_SR",
  "version": "2019.28.1.3",
  "description": "Make off-screen screen reader only text visible to make sure SR only text has meaning and purpose.",
  "homepage_url": "https://a11ycats.com.au",
  "author": "Laurence Lewis",
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "jquery-3.4.0.min.js"
      ],
      "css": [
        "show-screen-reader-text.css"
      ]
    }
  ],
  "browser_action": {
    "default_icon": "icons/sr-icon-48.png",
    "default_title": "Show SR"
  },
  "icons": {
    "16": "icons/sr-icon-16.png",
    "48": "icons/sr-icon-48.png",
    "64": "icons/sr-icon-64.png",
    "128": "icons/sr-icon-128.png"
  },
  "permissions": [
    "https://*/*",
    "http://*/*",
    "activeTab"
  ]
}