Examine source code of Custom Font Override

{
  "manifest_version": 2,
  "name": "Custom Font Override",
  "version": "1.0.2",
  "description": "Force all pages to use your preferred font with automatic fallback for missing glyphs",
  "author": "Lumens Nexus",
  "permissions": [
    "activeTab",
    "storage",
    "tabs"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icons/icon-48.png",
      "96": "icons/icon-96.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "css": [
        "override.css"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "custom-font-override@lumens-nexus.com",
      "strict_min_version": "109.0"
    }
  }
}