Examine source code of Simple Mood Tracker

{
  "manifest_version": 2,
  "name": "Simple Mood Tracker",
  "version": "1.0",
  "description": "Tracks user mood by letting them input it manually.",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{79c21de5-e83e-47e7-98af-a370098d64fc}"
    }
  }
}