Examine source code of mma-blindfold

{
  "manifest_version": 2,
  "name": "mma-blindfold",
  "description": "Adds an MMA Blindfold to Wikipedia pages.",
  "version": "0.1",
  "homepage_url": "https://github.com/activityworkshop/MmaBlindfold",
  "icons": {
    "48": "icons/mb-48.png",
    "96": "icons/mb-96.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "page_action": {
    "default_icon": "icons/off.svg",
    "browser_style": true,
    "show_matches": [
      "https://*.wikipedia.org/*"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.wikipedia.org/*"
      ],
      "js": [
        "content_scripts/updatepage.js"
      ]
    }
  ],
  "permissions": [
    "tabs",
    "cookies",
    "<all_urls>",
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{be38617f-0a3a-4cb5-a5c6-e0ee17c6aff1}"
    }
  }
}