Examine source code of Page Zoom

{
  "manifest_version": 2,
  "name": "Page Zoom",
  "description": "Sets default zoom for tabs.",
  "version": "0.1.1resigned1",
  "applications": {
    "gecko": {
      "id": "page-zoom@ris58h"
    }
  },
  "permissions": [
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}