Examine source code of Legacy Domains

{
  "name": "Legacy Domains",
  "version": "1.0.1",
  "author": "zoumath19",
  "icons": {
    "48": "icon.png"
  },
  "manifest_version": 2,
  "omnibox": {
    "keyword": "ld"
  },
  "background": {
    "scripts": [
      "background/background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{133b956d-04a5-4d33-b9a0-bbe984e330cc}"
    }
  }
}