Examine source code of Scratch 3 Developer Tools

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "description": "__MSG_extensionDescription__",
  "default_locale": "en",
  "author": "Griffpatch",
  "version": "1.24.3",
  "homepage_url": "https://www.griffpatch.co.uk",
  "icons": {
    "32": "images/favicon.png",
    "128": "images/bigIcon.png"
  },
  "browser_action": {
    "default_icon": "images/favicon.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "run_at": "document_start",
      "matches": [
        "https://scratch.mit.edu/projects/*",
        "https://llk.github.io/scratch-gui/*"
      ],
      "js": [
        "run-inject.js"
      ],
      "css": [
        "addon/userscript.css"
      ]
    }
  ],
  "web_accessible_resources": [
    "addon/*",
    "images/*",
    "inject/*",
    "libraries/*",
    "l10n/*"
  ]
}