Examine source code of Tabs Grid

{
  "manifest_version": 2,
  "name": "Tabs Grid",
  "version": "1.0",
  "description": "Shows all open tabs in a grid format.",
  "icons": {
    "48": "icons/tabs-grid.svg",
    "96": "icons/tabs-grid.svg"
  },
  "permissions": [
    "<all_urls>",
    "tabs"
  ],
  "browser_action": {
    "default_icon": "icons/tabs-grid.svg",
    "default_title": "Show tabs grid",
    "theme_icons": [
      {
        "light": "icons/tabs-grid-light.svg",
        "dark": "icons/tabs-grid.svg",
        "size": 16
      },
      {
        "light": "icons/tabs-grid-light.svg",
        "dark": "icons/tabs-grid.svg",
        "size": 32
      }
    ]
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}