Examine source code of Reader Mode Plus

{
  "manifest_version": 3,
  "name": "Reader Mode Plus",
  "version": "1.0",
  "description": "Enhances Firefox's built-in Reader View by offering more customization options like additional font choices, adjustable line height and character spacing, custom background themes (including dark mode variations), and text-to-speech integration. It also allows saving articles for offline reading.",
  "action": {
    "default_popup": "popup.html",
    "default_icon": "reader_mode_plus.png"
  },
  "icons": {
    "128": "reader_mode_plus.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "ekaykessleruess352@hotmail.com"
    }
  }
}