Examine source code of Tab Highlighter

{
  "manifest_version": 2,
  "name": "Tab Highlighter",
  "version": "1.0",
  "description": "Highlights active tab with yellow color",
  "permissions": [
    "tabs",
    "theme",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icon48.png",
    "default_title": "Yellow Tab Highlighter"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{3250e64b-5f38-456f-9174-5f5e1b1a80bc}"
    }
  }
}