Examine source code of 12ft

{
  "manifest_version": 2,
  "name": "12ft",
  "version": "1.0.3",
  "description": "Hop the paywall, browse a cleaner web",
  "author": "Thomas Millar",
  "icons": {
    "128": "icons/12ft-icon-dark-128.png"
  },
  "background": {
    "page": "background.html"
  },
  "browser_action": {
    "default_name": "12ft",
    "default_title": "12ft – Hop the paywall",
    "default_icon": {
      "128": "icons/12ft-icon-128.png"
    }
  },
  "permissions": [
    "storage",
    "tabs"
  ]
}