Names, revisions and addresses

main on Hugging Face is a moving branch. A model you tested last week can be a different set of bytes today under the same name. The hub gives every name a fixed meaning and every version a permanent address.

Names

A model is <owner>/<name>, exactly as on Hugging Face: hexgrad/Kokoro-82M. The hub is case-sensitive on the Hugging Face routes and lowercases the name on the OCI routes, because OCI repository names must be lowercase.

Revisions

The hub indexes one revision per model: the commit that was current when the index last ran. main on the hub means that revision, and nothing else.

curl -s https://gethologram.ai/api/models/hexgrad/Kokoro-82M/refs

{
  "branches": [{ "name": "main", "ref": "refs/heads/main", "targetCommit": "f3ff3571791e39611d31c381e3a41a3af07b4987" }],
  "tags": [],
  "converts": []
}

Asking for any other revision is refused with the one the hub has:

curl -s https://gethologram.ai/api/models/hexgrad/Kokoro-82M/revision/deadbeef

{ "error": "The hub has hexgrad/Kokoro-82M at f3ff3571791e39611d31c381e3a41a3af07b4987 only." }

A /resolve/ redirect always carries the full commit, never main, so the URL you are sent to is itself pinned:

Location: https://huggingface.co/hexgrad/Kokoro-82M/resolve/f3ff3571791e39611d31c381e3a41a3af07b4987/EVAL.md

Addresses

Under the names sits a content-addressed store. Every object in it is named by the BLAKE3 hash of its bytes, written blake3:<64 hex>. Two things follow:

• An address never changes meaning. A response under /api/v1/objects/<address> can be cached forever.
• A version is an address. To pin a model, keep its model address. To see history, follow prev.

The catalog's address changes daily; the descriptor at the root points at today's:

curl -s https://gethologram.ai/.well-known/model-hub.json

{
  "format": "hologram.model-hub.descriptor/v1",
  "catalog": "blake3:423d29497813ce4cb5a21cf5c50bf8fe6efa1a1f19dc203e0dec8e5bb21a516f",
  "snapshot": "2026-09-23",
  "fetch": "/api/v1/objects/{id}",
  …
}

Inside the catalog, each name maps to a model address and its sources:

"hexgrad/Kokoro-82M": {
  "model": "blake3:3cc11e52049117dfc397240fddc7a4d3aa392ded7f623986e4e5757371363d9e",
  "sources": ["blake3:1163c7df…", "blake3:6f5a0835…"]
}

And the model object holds the revision, the licence, every file with its SHA-256, and prev, the address of the revision before it, or null for the first one indexed:

curl -s https://gethologram.ai/api/v1/objects/blake3:3cc11e52049117dfc397240fddc7a4d3aa392ded7f623986e4e5757371363d9e

{
  "format": "hologram.model-hub.model/v1",
  "id": "hexgrad/Kokoro-82M",
  "revision": "f3ff3571791e39611d31c381e3a41a3af07b4987",
  "license": "apache-2.0",
  "prev": null,
  "files": [
    { "path": "EVAL.md", "size": 534, "sha256": "9b4d7a54809bf22127d19d936d9e749249e1a655e2e0a1df8a6546f77a819658", "weights": false },
    …
  ]
}

The manifest in a search row is this address, so a search result already tells you which version you will get.

Yesterday's hub

The catalog has prev too. Follow it and you are reading the index as it stood the day before, with every address still valid. /archive.json lists every day the hub has indexed, with the IPFS CID of each day's index.

curl -s https://gethologram.ai/archive.json | head -c 300

Next: where the bytes actually come from, in Sources and failover.