Examine source code of walkin-homepage

{
  "manifest_version": 2,
  "name": "walkin-homepage",
  "description": "walkin's homepage",
  "version": "0.2.3",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "96": "icon/96.png",
    "128": "icon/128.png"
  },
  "permissions": [
    "bookmarks",
    "storage",
    "webRequest"
  ],
  "chrome_settings_overrides": {
    "homepage": "newtab.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d40fa009-1963-4c52-b49a-4e8364df1e45}",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "background": {
    "persistent": true,
    "scripts": [
      "background.js"
    ]
  },
  "chrome_url_overrides": {
    "newtab": "newtab.html"
  }
}