Examine source code of Reload PAC button

{
  "manifest_version": 2,
  "author": "Timendum",
  "name": "Reload PAC button",
  "icons": {
    "32": "icon-32.png",
    "64": "icon-64.png"
  },
  "browser_action": {
    "browser_style": true,
    "default_title": "Reload PAC",
    "default_icon": {
      "32": "icon-32.png",
      "64": "icon-64.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "applications": {
    "gecko": {
      "id": "jid1-BAuVAdBr8gFlOQ@jetpack",
      "strict_min_version": "67.0a1"
    }
  },
  "description": "A button to reload the PAC definitions",
  "permissions": [
    "proxy",
    "notifications"
  ],
  "version": "0.3.1"
}