Examine source code of Always search words

{
  "manifest_version": 2,
  "name": "Always search",
  "version": "3.1",
  "description": "Permanent searching words on web pages. It's like Ctrl + F on all tabs.",
  "homepage_url": "https://github.com/timotheebeaugas/ctrl-f",
  "icons": {
    "48": "icons/search-48.png"
  },
  "permissions": [
    "activeTab",
    "tabs",
    "<all_urls>",
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "scripts/search.js",
        "popup/script.js"
      ]
    }
  ],
  "browser_action": {
    "default_icon": "icons/search-32.png",
    "default_title": "Always search",
    "default_popup": "popup/index.html"
  }
}