Examine source code of Content Highlighter

{
  "manifest_version": 2,
  "name": "Content Highlighter",
  "version": "1.0",
  "description": "Highlight and save notes from web pages.",
  "permissions": [
    "storage",
    "activeTab"
  ],
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html",
    "default_title": "Content Highlighter"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{abd94969-d71f-4a7b-912d-04f02b87be96}"
    }
  }
}