Examine source code of Main Search Selector

{
  "manifest_version": 2,
  "name": "Main Search Selector",
  "version": "0.9",
  "description": "Adds a ctrl-/ hotkey to select a page's main search input.",
  "icons": {
    "192": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "main-search-selector.js"
      ]
    }
  ]
}