Examine source code of Calculator Search

{
  "applications": {
    "gecko": {
      "id": "calculator-search@isaac-newt",
      "strict_min_version": "52.0"
    }
  },
  "manifest_version": 2,
  "name": "Calculator Search",
  "version": "0.0.3resigned1",
  "description": "get quick answers to basic math queries in the Awesomebar",
  "permissions": [],
  "omnibox": {
    "keyword": "calc"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}