Examine source code of Highlight Saver

{
  "manifest_version": 2,
  "name": "Highlight Saver",
  "version": "1.0.0",
  "description": "Select text on a page and save highlights locally into the extension popup.",
  "icons": {
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "highlight-saver@example.com"
    }
  },
  "permissions": [
    "storage",
    "activeTab"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Highlight Saver",
    "default_icon": "icons/icon-48.png",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "content_security_policy": "script-src 'self'; object-src 'self'"
}