Examine source code of KanjiStart

{
  "name": "KanjiStart",
  "version": "0.3.5",
  "manifest_version": 2,
  "description": "Replaces your New Tab page with a display for a randomly chosen kanji and some information about it.",
  "icons": {
    "16": "icon16.png",
    "32": "icon32.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{15efa947-940e-4dc3-9869-fb4d5abb8372}"
    }
  }
}