Examine source code of Follow Me Back

{
  "manifest_version": 3,
  "name": "Follow Me Back",
  "description": "See who doesn't follow you back on Instagram.",
  "version": "0.3.0",
  "license": "MPL-2.0",
  "icons": {
    "64": "icons/icon.png"
  },
  "action": {
    "default_icon": {
      "64": "icons/icon.png"
    },
    "default_popup": "action/index.html",
    "default_title": "Follow Me Back"
  },
  "permissions": [
    "activeTab",
    "storage",
    "scripting"
  ],
  "host_permissions": [
    "https://*.instagram.com/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{5e20c7d6-502a-477a-8703-3ec4e53b6825}"
    }
  }
}