Examine source code of Write on PDF

{
  "manifest_version": 3,
  "name": "Write on PDF",
  "version": "1.2.0",
  "description": "Type, Draw, Sign & Print PDFs instantly.",
  "homepage_url": "https://codekp.com",
  "browser_specific_settings": {
    "gecko": {
      "id": "write-on-pdf@codekp.com",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "storage",
    "unlimitedStorage",
    "webNavigation",
    "webRequest",
    "webRequestBlocking",
    "webRequestFilterResponse",
    "scripting",
    "tabs",
    "downloads",
    "declarativeNetRequestWithHostAccess"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "src/background.js"
    ],
    "type": "module"
  },
  "content_security_policy": {
    "extension_pages": "script-src 'self' 'wasm-unsafe-eval'; object-src 'self'"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "src/capture-main.js"
      ],
      "world": "MAIN",
      "run_at": "document_start",
      "all_frames": true,
      "match_about_blank": true
    },
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "src/capture-bridge.js"
      ],
      "world": "ISOLATED",
      "run_at": "document_start",
      "all_frames": true,
      "match_about_blank": true
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "src/viewer.html"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "action": {
    "default_popup": "src/popup.html",
    "default_title": "Write on PDF",
    "default_icon": {
      "16": "icons/icon16.png",
      "32": "icons/icon32.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  }
}