Examine source code of Slow Down

{
  "description": "Cuts out distractions by forcing you to wait before entering distracting websites.",
  "manifest_version": 2,
  "name": "Slow Down",
  "version": "0.0.2",
  "browser_action": {
    "default_title": "Slow Down"
  },
  "permissions": [
    "storage",
    "tabs"
  ],
  "options_ui": {
    "page": "options.html",
    "browser_style": true
  },
  "applications": {
    "gecko": {
      "id": "slow-down@nicholasrebstock.com",
      "strict_min_version": "57.0a1"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}