Examine source code of Preact Developer Tools

{
  "manifest_version": 2,
  "name": "Preact Developer Tools",
  "description": "Adds debugging tools for Preact to Firefox",
  "version": "4.7.2",
  "devtools_page": "panel/empty-panel.html",
  "content_security_policy": "script-src 'self' 'unsafe-eval'; object-src 'self'",
  "permissions": [
    "file:///*",
    "http://*/*",
    "https://*/*",
    "storage"
  ],
  "applications": {
    "gecko": {
      "id": "devtools@marvinh.dev"
    }
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png",
    "192": "icons/icon-192.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "icons/icon-16-disabled.png",
      "32": "icons/icon-32-disabled.png",
      "48": "icons/icon-48-disabled.png",
      "128": "icons/icon-128-disabled.png",
      "192": "icons/icon-192-disabled.png"
    },
    "default_popup": "popup/disabled.html"
  },
  "background": {
    "scripts": [
      "background/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-script.js"
      ],
      "all_frames": true,
      "run_at": "document_start"
    }
  ],
  "web_accessible_resources": [
    "preact-devtools-page.css"
  ]
}