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" 
  }
}