What values can --front-end-version take, where does ComfyUI download that frontend from, and where does it store it?

Problem. Pinning the ComfyUI web frontend independently of the core install. Conditions. Any launch of main.py without --front-end-root. Method. Pass --front-end-version owner/repo@version. The regex accepts owner (alphanumeric/hyphen, up to 39 chars), repo, and version as latest, prerelease, or X.Y.Z with optional v prefix and suffix. The default comfyanonymous/ComfyUI@latest does NOT download anything: it uses the pip package comfyui-frontend-package at the version requirements.txt pins. Any other value queries the GitHub Releases API for that owner/repo, matches tag_name against the value or v-prefixed value, downloads the release asset named dist.zip and unzips it into web_custom_versions/<owner>_<repo>/<version> inside the ComfyUI checkout. A v-prefixed pin reuses an existing folder without network. Failure modes. A missing release raises ValueError; a release without dist.zip raises ValueError. GitHub rate limits or no internet also fail (see C3-B807-02). Limitations. Third-party repos run whatever JS is in their dist.zip with no checksum check seen in these files. Version and date. ComfyUI commit fb3befd, read 2026-10-24. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Limitations: Source read at one commit only; later commits may change the pattern. The help text says only latest or a number but the code also accepts prerelease; I did not run ComfyUI to confirm behaviour. Checksum or signature verification absent only as far as these two files show. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://raw.githubusercontent.com/comfyanonymous/ComfyUI/fb3befd168731438f88bc96e0920a538e8649878/comfy/cli_args.py",
      "note": "cli_args.py --front-end-version help; parse_version_string VERSION_PATTERN; download_release_asset_zip; FrontendManager.CUSTOM_FRONTENDS_ROOT; init_frontend_unsafe; researcher reasoning"
    },
    {
      "url": "https://raw.githubusercontent.com/comfyanonymous/ComfyUI/fb3befd168731438f88bc96e0920a538e8649878/app/frontend_management.py",
      "note": "cli_args.py --front-end-version help; parse_version_string VERSION_PATTERN; download_release_asset_zip; FrontendManager.CUSTOM_FRONTENDS_ROOT; init_frontend_unsafe; researcher reasoning"
    }
  ]
}