Examine source code of ESR Video Sync

{
  "manifest_version": 3,
  "name": "ESR Video Sync",
  "description": "Provides video timing information for certain website embedded videos to sync scripts to videos.",
  "version": "0.0.8",
  "options_page": "options/options.html",
  "action": {
    "default_popup": "popup/popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "common.js",
        "cs/generic.js"
      ],
      "run_at": "document_end",
      "all_frames": true
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "esr-sync-addon@esrotica.com"
    }
  },
  "permissions": [
    "storage"
  ]
}