Examine source code of Slack Chrome UA Spoofer

{
  "manifest_version": 2,
  "name": "Slack Chrome UA Spoofer",
  "version": "1.0.0",
  "description": "Reports a Chrome-on-Windows User-Agent to slack.com so Slack unlocks the 'Sync with OS' automatic theme setting in Firefox-based browsers (Zen, LibreWolf, etc.).",
  "browser_specific_settings": {
    "gecko": {
      "id": "slack-chrome-ua@local.extension",
      "strict_min_version": "91.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "*://*.slack.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.slack.com/*"
      ],
      "js": [
        "inject.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ],
  "icons": {
    "48": "icon.svg",
    "96": "icon.svg"
  }
}