Examine source code of Gem DevTools

{
  "$schema": "https://raw.githubusercontent.com/extend-chrome/manifest-json-schema/main/schema/manifest.schema.json",
  "name": "Gem DevTools",
  "version": "2.2.4",
  "manifest_version": 3,
  "description": "Gem DevTools Extension to inspect and debug Gem elements",
  "devtools_page": "devtools.html",
  "browser_specific_settings": {
    "gecko": {
      "id": "{2af13fd2-a726-41de-b3a1-4bf2cb91c105}"
    }
  },
  "content_scripts": [
    {
      "world": "MAIN",
      "all_frames": true,
      "match_about_blank": true,
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "icons": {
    "512": "logo.png"
  }
}