Examine source code of FontShifter

{
  "manifest_version": 3,
  "name": "FontShifter",
  "version": "3.0",
  "description": "Change website fonts with per-site or global settings, with robust dynamic content support.",
  "browser_specific_settings": {
    "gecko": {
      "id": "fontshifter@divslayer.github.io",
      "strict_min_version": "128.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "storage",
    "tabs"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "32": "icons/icon32.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "injector.js"
      ],
      "run_at": "document_start",
      "world": "MAIN",
      "all_frames": true
    },
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content_script.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "fonts/*.woff2"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ]
}