Examine source code of Page Zoom Controller

{
  "manifest_version": 2,
  "name": "Page Zoom Controller",
  "version": "1.0",
  "description": "Adjust the zoom level of any webpage with a slider and save preferences per site. Features a sleek, monochrome interface.",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{6c55b73b-9c81-4ea5-bbcf-b287ed64bf18}"
    }
  }
}