Examine source code of Cloud Marks

{
  "manifest_version": 2,
  "name": "Cloud Marks",
  "version": "0.3.1",
  "description": "This extension provide the function to export or import bookmarks with cloud storage services.",
  "author": "xia@silvia.com",
  "homepage_url": "https://github.com/xia-sava/cloud-marks",
  "browser_specific_settings": {
    "gecko": {
      "id": "{0B97FA0E-451B-11E8-A9DA-41A2F3E0CD91}"
    }
  },
  "permissions": [
    "bookmarks",
    "identity",
    "storage",
    "alarms",
    "https://accounts.google.com/*",
    "https://www.googleapis.com/*",
    "https://*.amazonaws.com/"
  ],
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "icons": {
    "512": "icons/cloud-marks.png"
  },
  "background": {
    "scripts": [
      "js/service_worker.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "512": "icons/cloud-marks.png"
    },
    "default_title": "cloud marks",
    "default_popup": "html/popup.html"
  },
  "options_ui": {
    "page": "html/options.html"
  }
}