Examine source code of Switch between http-S

{
  "manifest_version": 2,
  "name": "Switch between http S",
  "version": "1.2",
  "description": "A button to quickly manually switch between httpS and http for current tab",
  "homepage_url": "https://garywill.github.io",
  "developer": {
    "name": "Garywill",
    "url": "https://github.com/garywill/switch-between-http-s"
  },
  "icons": {
    "128": "icon.svg"
  },
  "permissions": [
    "tabs",
    "activeTab"
  ],
  "page_action": {
    "default_icon": "icon.svg",
    "default_title": "Switch between httpS and http",
    "show_matches": [
      "http://*/*",
      "https://*/*"
    ]
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}