Examine source code of FABigation

{
  "manifest_version": 3,
  "name": "FABigation",
  "version": "1.4",
  "description": "FABulous gesture navigation.",
  "icons": {
    "48": "icons/FAB48.png",
    "96": "icons/FAB96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "JS-FABigation.js"
      ]
    }
  ],
  "action": {
    "default_icon": "icons/FAB96.png",
    "default_title": "FABigation",
    "default_popup": "settings/options.html"
  },
  "options_ui": {
    "page": "settings/options.html"
  },
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "FABigation@houbo.org"
    }
  }
}