Examine source code of One-click Container

{
  "manifest_version": 2,
  "name": "One-Click Container",
  "description": "Confine every site to either an ephemeral container or a site specific container",
  "version": "1.11.2",
  "icons": {
    "48": "icons/48.png"
  },
  "permissions": [
    "<all_urls>",
    "cookies",
    "contextualIdentities",
    "storage",
    "tabs",
    "menus",
    "webRequestBlocking",
    "webRequest"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "browser_style": true,
    "default_popup": "page.html",
    "default_icon": "icons/32.png",
    "default_title": "Toggle container between confined and ephemeral"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{9d524b92-88de-4972-8aef-0eae65b1c4e2}"
    }
  }
}