Examine source code of OpenAPI DevTools

{
  "manifest_version": 3,
  "name": "OpenAPI DevTools",
  "version": "1.5.2",
  "devtools_page": "index.html",
  "permissions": [],
  "icons": {
    "16": "icon16.png",
    "32": "icon32.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "andrew@awalsh.io"
    }
  }
}