Examine source code of Clean Reader

{
  "name": "Clean Reader",
  "version": "1.0",
  "icons": {
    "88": "icons.png"
  },
  "description": "Clean Reader by ccgauche | Clean reader make for a clean, simpler, greener web.",
  "permissions": [
    "<all_urls>",
    "contextMenus",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "cr.js"
      ]
    }
  ],
  "browser_action": {
    "default_popup": "popup.html"
  },
  "manifest_version": 2
}