electron/spec/fixtures/extensions/red-bg/manifest.json

{
  "name": "red-bg",
  "version": "1.0",
  "content_scripts": [
    {
      "matches": ["<all_urls>"],
      "js": ["main.js"],
      "run_at": "document_start"
    }
  ],
  "manifest_version": 2
}