Examine source code of Containerise

{
  "manifest_version": 2,
  "name": "Containerise",
  "version": "3.9.0",
  "description": "Firefox extension to automatically open websites in a container",
  "icons": {
    "48": "icons/icon.png",
    "96": "icons/icon.png"
  },
  "permissions": [
    "contextualIdentities",
    "cookies",
    "tabs",
    "webRequest",
    "webRequestBlocking",
    "storage",
    "<all_urls>"
  ],
  "browser_action": {
    "browser_style": true,
    "default_title": "Containerise",
    "default_popup": "ui/index.html",
    "default_icon": "icons/icon.png"
  },
  "background": {
    "scripts": [
      "index.js"
    ]
  },
  "applications": {
    "gecko": {
      "id": "containerise@kinte.sh",
      "strict_min_version": "53.0"
    }
  },
  "options_ui": {
    "page": "ui-preferences/index.html"
  }
}