Examine source code of Reading Goals Tracker

{
  "manifest_version": 2,
  "name": "Reading Goals Tracker",
  "version": "1.0",
  "description": "Set daily word count goals.",
  "permissions": [
    "activeTab",
    "storage",
    "tabs"
  ],
  "browser_action": {
    "default_title": "Reading Goals Tracker",
    "default_popup": "popup.html"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{3672ba03-9f79-455f-a65d-698ae2cbaef5}"
    }
  }
}