Examine source code of b2ntp

{
  "manifest_version": 2,
  "name": "b2ntp",
  "description": "Simple and powerful New Tab Page with your bookmarks",
  "version": "1.0.3",
  "chrome_url_overrides": {
    "newtab": "blank.html"
  },
  "browser_action": {
    "default_icon": "./src/png/256x256.png"
  },
  "icons": {
    "20": "src/png/20x20.png",
    "48": "src/png/48x48.png",
    "128": "src/png/128x128.png",
    "256": "src/png/256x256.png"
  },
  "permissions": [
    "bookmarks"
  ]
}