Examine source code of Multi Search Engine

{
  "name": "Multi Search Engine",
  "description": "Type : followed by custom Suggestion or perdefined search engines to search",
  "version": "2.1resigned1",
  "icons": {
    "48": "icons/search-icon.png"
  },
  "applications": {
    "gecko": {
      "strict_min_version": "52.0a1",
      "id": "{3cb19d3a-5139-443b-9430-b66f904ed316}"
    }
  },
  "omnibox": {
    "keyword": "ms"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "tabs"
  ],
  "manifest_version": 2
}