Examine source code of Enable Select

{
  "manifest_version": 2,
  "name": "Enable Select",
  "version": "1.0",
  "author": "Sarthak Jain",
  "description": "This plugin helps enable text selection on websites.",
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "48": "icons/EnableSelect48.png",
      "96": "icons/EnableSelect96.png"
    },
    "default_title": "Enable Select",
    "default_popup": "interface/popup.html"
  },
  "icons": {
    "48": "icons/EnableSelect48.png",
    "96": "icons/EnableSelect96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "EnableSelect.js"
      ],
      "run_at": "document_end"
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "permissions": [
    "storage",
    "tabs",
    "activeTab",
    "unlimitedStorage",
    "background"
  ]
}