Examine source code of Visit Counter

{
  "manifest_version": 2,
  "name": "Visit Counter",
  "description": "Counts how often you visit which websites.",
  "homepage_url": "https://github.com/azadad96",
  "version": "2.2",
  "browser_specific_settings": {
    "gecko": {
      "id": "{5306e664-1071-409a-8cab-fc9a3c24828b}"
    }
  },
  "icons": {
    "96": "icon96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "visit.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "showdata.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "96": "icon96.png"
    },
    "default_title": "Visit Counter"
  },
  "permissions": [
    "storage",
    "unlimitedStorage"
  ]
}