Examine source code of timewhitelist

{
  "manifest_version": 2,
  "name": "timewhitelist",
  "description": "Block all sites except those on whitelists. Blacklist removes sites from whitelist.",
  "version": "0.6.0",
  "author": "serv-inc",
  "homepage_url": "https://github.com/serv-inc/timelist",
  "short_name": "block urls with wall time",
  "applications": {
    "gecko": {
      "id": "timewhitelist@serv-inc.github.com"
    }
  },
  "icons": {
    "128": "clipboard-list-solid.png"
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "background": {
    "scripts": [
      "settings.js",
      "background.js"
    ]
  },
  "storage": {
    "managed_schema": "schema.json"
  }
}